Full text of DOI:10.1093/japr/10.1.24

2001 Poultry Science Association, Inc.
E
FFECTS OF
B
ODY
RE-
ROILER
ERFORMANCE
W
EIGHT
EAK EEDING
REEDER
U
NIFORMITY AND
P
P
F
P
ROGRAMS ON
B
B
HEN
P
B. P. HUDSON, R. J. LIEN1, and J. B. HESS
Department of Poultry Science, Auburn University,
Auburn, Alabama 36849-5416
Phone: (334) 844-2609
Fax: (334) 844-2641
Primary Audience: Breeder Managers, Nutritionists, Researchers
SUMMARY
This study examined the effects of body weight (BW) uniformity on broiler breeder hen
performance as well as the effects of post-lighting feeding programs on the uniformity and
performance of nonuniform groups. Eight hundred Cobb-500 strain breeder females were housed
in floor pens at 20 weeks of age. The HT treatment, which consisted of pullets that each weighed
between 4.1 and 4.5 lb at housing, had high (H) uniformity and received typical (T) feed increases.
Three other treatments contained 25 light (3.4 to 3.8 lb) and 25 heavy (4.8 to 5.2 lb) birds in each
pen. These treatments had low (L) uniformity and were subject to either T (LT) or fast (F) (LF)
increases in pre-peak feed allotments or skip-a-day (S) feeding (LS) until 25 weeks of age. Results
indicated that H initial uniformity was associated with increased egg production, and F feed
allotment increases stimulated early egg production. The onset of lay was delayed in birds on the
LS treatment, causing a decline in cumulative egg production and an increase in mean egg weight;
but weekly egg production levels had recovered by 30 weeks. Modifications to pre-peak feeding
programs may be an effective method to improve uniformity of nonuniform flocks.
Key words: Broiler breeder, body weight uniformity, feeding programs, egg production, egg weight
2001 J. Appl. Poultry Res. 10:24–32
pullets should be within 15% of the average
D
ESCRIPTION OF
P
ROBLEM
BW. Uniformity provides an estimate of the
variability in a given flock at a given age, and,
generally speaking, the more uniform the flock,
the better the performance of that flock [1].
A highly uniform flock will reach peak egg
production earlier and will peak higher than a
nonuniform flock [3]. Nonuniform flocks gener-
ally do not attain high egg production peaks
because of the varying degrees of maturity
Uniformity of BW in broiler breeder flocks
is usually determined by individually weighing
a sample of birds, calculating the average BW,
determining the limits 15% above and below the
average, and finally calculating the percentage
of birds whose BW are within those limits [1].
The Cobb Breeder Management Guide [2] states
that, in a “uniform” flock of pullets, 80% of
1 To whom correspondence should be addressed

HUDSON ET AL.: UNIFORMITY AND FEEDING PROGRAM
25
TABLE 1. Contents of feeds provided to broiler breeder
hens. (Ingredients and nutrients appear in subtitles)
among the individual hens [3, 4]. Low peak
production in nonuniform flocks is due to vari-
ability in sexual maturation, resulting in a de-
layed onset of production in light hens [5] and
accelerated production in heavy hens [6]. Sett-
able egg production is expected to be poor even
if a nonuniform flock is at the target mean BW
[7] because underweight hens may produce eggs
that vary greatly in size and hens above target
BW produce a greater percentage of double-
yolked eggs [8]. Peak usually is not consistent,
and egg size distribution is expected to be un-
even in nonuniform flocks [4]. It has been re-
ported that the lower the BW uniformity is at
sexual maturity, the later and lower the peak egg
production and the fewer eggs produced when
the flock is liquidated [3]. Pettite et al. [7] re-
ported that BW uniformity (80 vs. 89%) did
not influence cumulative egg production, egg
weight, fertility, or mortality; but the more uni-
form treatment had significantly higher egg pro-
duction during the first 10 weeks of lay.
INGREDIENT (%)
PREBREEDER
BREEDER
Corn
70.18
21.25
2.75
2.75
1.80
0.38
0.05
0.10
0.50
0.25
66.88
22.05
—
6.70
1.85
0.38
0.10
1.30
0.50
0.25
Soybean meal
Rice mill feed
Limestone
Dicalcium phosphate
Salt
DL-Met
Poultry oil
Vitamin premix
Mineral premix
NUTRIENTSA
CP (%)
ME (kcal/lb)
Fat (%)
16.00
2,922
3.01
16.00
2,922
3.93
Ca (%)
1.50
3.01
Met + Cys (%)
Met (%)
0.58
0.33
0.63
0.38
Lys (%)
0.81
0.82
ACalculated values.
There are several factors that may contribute
to low BW uniformity. It is estimated that >35%
of the variation in mature BW in Leghorn flocks
is due to variation in hatching egg size [9]. It
has also been suggested that social dominance
by larger birds prevents smaller birds from con-
suming their fair share of feed, which may result
in a decrease in uniformity [3]. Other factors that
may influence uniformity are feed distribution
speed [4]; genetic variability in parent stock [5];
bird density; amount, or quality of feed, or both;
availability of feeder and waterer space; diseases
or parasites; house temperatures; and ventila-
tion [1].
Low uniformity has been a problem associ-
ated with breeder flocks since the use of highly
restrictive feeding programs was initiated. Over-
weight hens in nonuniform flocks represent a
major economic loss because of their decreased
production and overconsumption of feed [10].
The delayed onset of lay of lighter hens may
also result in economic losses. The scale of these
losses is difficult to assess but is likely signifi-
cant. When poor uniformity occurs, birds may
be separated by BW and managed differently to
help regain uniformity [1, 2, 11, 12], but this task
may be labor-intensive and costly. Relieving this
problem entirely is impossible, but it may be
alleviated significantly through alterations in
feeding programs provided during the period
immediately following photostimulation. With
these observations in mind, this study was con-
ducted to determine the effects of uniformity on
hen performance, as well as the influences of
different pre-peak feeding programs on perfor-
mance and uniformity of nonuniform groups.
MATERIALS AND
M
ETHODS
Eight hundred Cobb-500 broiler breeder pul-
lets were obtained from a commercial pullet
house at 20 weeks of age. They were wing-
banded and then moved to and housed in floor
pens at the Auburn University Poultry Research
Unit. Treatments were based on uniformity of
BW at 20 weeks as well as pre-peak feeding
programs. In each of four replicate floor pens
(82.5 ft2 per pen) were placed 50 pullets that
each weighed between 4.1 and 4.5 lb at housing.
This was called the H BW uniformity treatment.
In each of the 12 remaining replicate pens were
placed 50 pullets, 25 of which weighed between
3.4 and 3.8 lb (light), and 25 of which weighed
between 4.8 and 5.2 lb (heavy). These pens had
L uniformity. All pens had similar BW means
at initiation of the trial. Common prebreeder and
breeder diets were provided for all treatments
from 20 to 23 weeks and 23 to 35 weeks, respec-

26
JAPR: Research Report
tively (Table 1). The H uniformity pens and four
of the L uniformity pens received T pre-peak
feed allotment increases that increased to a peak
of 34.0 lb/100 birds per day during Week 29
(Table 2). Four of the remaining L pens were
subject to increases in pre-peak feed allotments
(LF), which reached the same peak allotments
during Week 27 (Table 2). The final four L pens
were provided weekly intakes similar to those
of the T treatments, but feed was provided on
4 of 7 days per week until 25 weeks. This treat-
ment will be referred to as the LS treatment. All
other treatments were fed daily from 20 weeks
until the end of the trial. Treatment S feed allot-
ments were increased more rapidly relative to
the T treatments, from 24 to 27 weeks, because
of poor feed efficiency and delayed onset of lay.
Skip-a-day feeding was practiced until 20 weeks
for the other three treatments. Therefore, the
four treatments were HT, LT, LF, and LS (which
was fed 4 of 7 days/wk until 25 weeks).
pen uniformity were determined weekly from
20 to 35 weeks. Birds on treatment LS were
weighed on “off feed” days. In each nonuniform
pen, average BW was determined for both the
light and heavy groups of birds to monitor the
progression of each of these subpopulations.
Eggs were picked up four times daily, and the
total production of normal (single-yolked and
intact), cracked, double-yolked, very small, mis-
shapen, thin-shelled, and soft-shelled eggs by
each pen were recorded daily. Weights of all
normal eggs produced were determined daily.
Egg weight uniformity was determined weekly
by first calculating the average egg weight for
each treatment, then calculating the percentage
of eggs that weighed within 5% of the average
weight. Double-yolked eggs were not included
in egg weight or uniformity determinations. Four
birds per pen were killed at 21, 25, and 30 weeks
of age. In the L uniformity pens, two heavy and
two light birds were killed at each sampling
time. In an effort to not alter uniformity of the
pens, birds weighing about 2.5% above and be-
low their pen (HT treatment) or BW group (LT,
LF, and LS treatments) mean were killed. Ovary,
oviduct, breast, and abdominal fat pad weights
All pullets were subjected to 8 hr of light
and 16 hr of darkness with an intensity between
0.5 and 1.0 fc at floor level from 3 to 20 weeks
of age. They were photostimulated at 21 weeks
with 15 hr of light and 9 hr of darkness, provid-
ing an intensity of >2 fc. Individual BW and
TABLE 2. Limited feed allotments provided to broiler breeder hens with either high or low uniformity. Hens were
provided different prepeak feeding programs
TREATMENTA
WEEK
HT
LT
LF
LS
(lb/100 bird/day)
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
19.25B
20.50
22.00
23.00
24.75
26.75
29.00
31.00
33.00
34.00
34.00
34.00
33.00
32.00
31.80
31.60
19.25B
20.50
22.00
23.00
24.75
26.75
29.00
31.00
33.00
34.00
34.00
34.00
33.00
32.00
31.80
31.60
19.25B
21.00
23.00
24.50
27.00
30.00
33.50
34.00
34.00
34.00
34.00
34.00
33.00
32.00
31.80
31.60
19.25B
20.50B
22.00B
23.00B
25.50B
28.50B
30.00
31.50
33.00
34.00
34.00
34.00
33.00
32.00
31.80
31.60
AIndicates uniformity and prepeak feeding program (Uniformity: H = high, L = low; feeding program: T = typical, F = fast
increase, and S = skip-a- day).
BIndicates S feeding. Otherwise, allotments were provided daily.

HUDSON ET AL.: UNIFORMITY AND FEEDING PROGRAM
27
TABLE 3. Breast, abdominal fat, and body weights of broiler breeder hens with high or low uniformities. Hens
were provided different prepeak feeding programs
TREATMENTA
WEEK
HT
LT
LF
LS
p
SEM
BODY WEIGHT (lb)
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
4.27
4.30
4.28
4.33
0.4551
0.0001
0.0001
0.0001
0.0001
0.0001
0.0001
0.0001
0.0001
0.0007
0.0028
0.0259
0.0917
0.0586
0.2116
0.2129
0.03
0.02
0.03
0.02
0.02
0.02
0.02
0.03
0.04
0.05
0.04
0.06
0.07
0.07
0.06
0.06
4.72a
5.14b
5.47b
5.78b
6.09b
6.59b
6.85c
7.02b
7.13b
7.30b
7.45b
7.50
4.75a
5.14b
5.48b
5.83b
6.14b
6.61b
6.86c
7.07b
7.13b
7.33b
7.46b
7.52
4.79a
5.26a
5.59a
5.99a
6.39a
6.93a
7.23a
7.36a
7.43a
7.56a
7.67a
7.74
4.59b
4.82c
5.11c
5.34c
5.74c
6.61b
7.00b
7.29a
7.39a
7.51a
7.66a
7.69
7.49b
7.56
7.63
7.56ab
7.59
7.61
7.73a
7.73
7.77
7.71ab
7.69
7.75
BREAST WEIGHT (g)
21
25
30
409.0b
588.1
649.2
407.3b
596.4
652.0
420.0ab
607.8
670.4
441.9a
574.4
682.6
0.0469
0.2800
0.5128
8.4
11.7
77.5
ABDOMINAL FAT WEIGHT (g)
21
25
30
11.3
15.8
12.5
15.3
0.6184
0.0812
0.0154
2.7
3.1
6.3
49.3b
63.9b
53.0ab
67.0b
61.8a
74.2ab
54.1ab
95.9a
AIndicates uniformity and prepeak feeding program (Uniformity: H = high, L = low; feeding program: T = typical, F = fast
increase, and S = skip-a-day to 25 weeks).
a–cMeans within a row without a common superscript differ significantly (p < 0.10).
as well as number of large yellow follicles
(>0.40 in.) were determined.
Data were analyzed using the General Linear
Models procedure of SAS௡ [13]; pens served as
the experimental unit (n = 4 per treatment). Data
were analyzed separately for each age, and data
were also analyzed on a cumulative basis when
applicable. When p values of <0.10 occurred,
means were separated using the Tukey’s Stu-
dentized Range Test.
R
ESULTS AND
D
ISCUSSION
The mean BW of birds on the HT and LT
treatments were similar throughout the trial, but
those of birds on the LF treatment were consis-
tently higher because of their faster feed allot-
ment increases (Tables 2 and 3). The mean BW
of birds on treatment LS was lowest through
FIGURE 1. Uniformity of broiler breeder hens with high
(H) or low (L) uniformity. Hens were provided different
prepeak feeding programs. Acronyms inside legend
represent uniformity and feeding program (T = typical,
F = fast increases, and S = skip-a-day to 25 weeks).
BW = body weight.

28
JAPR: Research Report
TABLE 4. Body weight gain from 20 to 30 weeks of birds
with light and heavy body weights on low uniformity
treatments
ing large quantities of feed when using an S
program may lead to a higher incidence of chok-
ing [1], but there were no treatment effects on
mortality (data not provided).
WEIGHT GAIN (lb)
TREATMENTA
Body weight uniformity remained above
90% during the entire trial for birds on treatment
HT but decreased slightly with age (Figure 1).
After 30 weeks, uniformity was similar among
birds on treatments HT, LF, and LS but remained
low for birds on treatment LT (Figure 1). Unifor-
mity increased up to 28 weeks for birds on all
L uniformity treatments. However, from 28 to
35 weeks, uniformity seemed to decrease
slightly for birds on the LT treatment and re-
mained relatively constant for birds on the LS
treatment. Birds on the LF treatment had higher
BW means and continually increasing unifor-
mity up to 35 weeks. It should be taken into
consideration that, as actual mean BW of a flock
varies increasingly from the target BW, the uni-
formity becomes less of a concern. For example,
a flock with a high percentage of overweight
hens may have high uniformity but will probably
perform poorly because of excessive BW. In-
creases in BW uniformity prior to peak egg pro-
duction may be due to decreased growth rate of
heavy hens, which have begun to produce eggs;
lighter hens, which have not yet initiated produc-
tion, continue to grow at a rapid rate. A signifi-
cant amount of BW gain occurs just prior to
the initiation of production because of the rapid
development of the ovary and oviduct. Pro-
longed S feeding also resulted in significant in-
LT
LF
LS
p
3.02b
3.29a
3.18ab
0.0600
0.07
SEM
BODY WEIGHT GROUP
Light
Heavy
p
3.52a
2.81b
0.0001
0.06
SEM
AIndicates uniformity and prepeak feeding program
(Uniformity: L = low feeding program, T = typical, F = fast
increase, and S = skip-a-day to 25 weeks).
a–bMeans within a treatment or body weight group without
a common superscript differ significantly (p < 0.10).
25 weeks but increased when allotments were
increased relative to the T treatments during
weeks 24 to 27; daily allotments were provided
after 25 weeks (Table 3). The lower initial BW
and rapid increase in BW when treatment LS
was switched to daily feeding may be attributed
to poor feed efficiency associated with S feeding
[14, 15] and the fact that these birds were being
weighed on “off-feed” days. More feed was pro-
vided to birds on the LS treatment than to birds
on the T treatments during weeks 24 to 27 to
increase BW gains and stimulate the onset of
lay (Table 2). It has been stipulated that provid-
TABLE 5. Influence of uniformity and prepeak feeding program on egg production of broiler breeders to 35 weeks
TREATMENTA
HT
LT
LF
LS
p
SEM
Total eggs per hen
Settable eggs per hen
DYB (eggs per hen)
Small eggs per hen
Days to 20% HDPC
Days to 50% HDP
Days to 80% HDP
HDP (24 to 35 weeks)
Egg weight (g)
52.0a
45.0a
0.9
49.4ab
42.3ab
0.9
50.4ab
42.9ab
1.3
46.8b
40.6b
0.9
0.0371
0.0283
0.1126
0.2131
0.0002
0.0005
0.0324
0.0368
0.0399
1.1
0.9
0.1
0.4
1.1
0.9
2.0
1.3
0.2
4.6
4.5
4.2
3.4
176.8b
184.3b
196.8b
61.9a
56.9ab
175.5b
186.0b
204.3a
58.8ab
56.4b
176.3b
183.3b
198.5ab
60.0ab
56.9ab
184.8a
190.3a
204.8a
55.7b
57.5a
AIndicates body weight uniformity and prepeak feeding program (Uniformity: H = high, L = low; feeding program: T =
typical, F = fast increase, and S = skip-a-day to 25 weeks).
BDY = double-yolked eggs.
CHDP = .
a–cMeans within a row without a common superscript differ significantly (p < 0.10).

HUDSON ET AL.: UNIFORMITY AND FEEDING PROGRAM
29
feed [3]. Our results indicate that light birds in
nonuniform flocks may, in fact, be consuming
adequate amounts of feed because they gained
more weight than the heavy birds from 20 to 30
weeks of age (Table 4). Light hens might have
gained more weight because they likely pro-
duced fewer eggs than heavy hens during this
period and had more nutrients available for
growth. If the trial would have been carried
through the entire production period, heavy hens
might have gained more weight late in lay be-
cause of earlier cessation of egg production.
Higher feed intakes led to increased abdomi-
nal fat weights in birds on the LF and LS treat-
ments at 30 weeks (Table 3). Breast weights
were similar among all treatments at both 25 and
30 weeks (Table 3). Heavy birds on nonuniform
treatments consistently had greater abdominal
fat and breast weight averages than did light
birds (data not provided). There were no treat-
ment effects on follicle number, oviduct, or
ovary weights at 21, 25, or 30 weeks (data not
provided).
FIGURE 2. Effects of uniformity and prepeak feeding
program on egg production by broiler breeder hens.
Acronyms inside legend represent uniformity (H = high;
L = low) and feeding program (T = typical, F = fast
increases, and S = skip-a-day to 25 weeks).
creases in uniformity, perhaps because of its
effect on eating habits; Lilburn [15] proposed
that birds ate less aggressively after prolonged
S feeding. Because feed is available for longer
periods of time when provided on an S program,
the larger and more aggressive birds may be
consuming feed immediately after it is provided,
allowing smaller and less aggressive birds to eat
adequate amounts of feed afterward. Research-
ers have stipulated that heavy birds in nonuni-
form flocks consume more than their share of
feed, and light birds do not consume enough
Age at 20% and 50% hen-day production
was approximately 7 days greater in hens on the
LS treatment (Table 5). The onset of lay lagged
for birds on the LS treatment (Figure 2), proba-
bly because that group included more pullets that
had not yet reached adequate BW for maturity
(Table 3). Egg production of hens on the LS
treatment was similar to that of birds on the LT
and LF treatments during Weeks 29 through 34
TABLE 6. Influence of body weight uniformity and prepeak feeding program on egg weight uniformityA
TREATMENTB
WEEK
HT
LT
LF
LS
p
SEM
24
25
26
27
28
29
30
31
32
33
34
35
20.0a
22.8
32.5a
33.6a
47.0a
52.9a
50.9
48.7
52.5
53.9
49.8
52.7
15.0b
26.1
35.0a
20.1
30.6a
35.3a
44.1a
47.9ab
49.1
51.3
52.2
51.2
52.3
51.8
—
8.2
0.0179
0.1449
0.0226
0.0012
0.0218
0.0619
0.5200
0.9339
0.5398
0.4972
0.8401
0.6146
4.1
5.3
4.0
2.7
3.4
2.9
3.2
3.3
2.8
3.0
3.0
3.5
29.6a
38.3a
42.2ab
47.3ab
46.8
14.0b
18.7b
30.4b
40.2b
44.3
48.9
49.0
47.4
49.8
51.7
49.2
47.4
49.6
48.6
46.6
APercentage of eggs with 5% of mean egg weight.
BIndicates body weight uniformity and prepeak feeding program (Uniformity: H = high, L = low; feeding program: T =
typical, F = fast increase, and S = skip-a-day to 25 weeks).
a–bMeans within a row without a common superscript differ significantly (p < 0.10).

30
JAPR: Research Report
birds that experienced decreased egg production
early in the production period had greater pro-
duction later [16]. This trend appeared to be
occurring for birds on the LS treatment in this
study and, had it been continued to a normal
FIGURE 3. Effects of uniformity and prepeak feeding
program on body weight distribution of broiler breeder
hens at 27, 31, and 35 weeks. Acronyms inside legend
represent uniformity (H = high; L = low) and feeding
program (T = typical, F = fast increases, and S = skip-
a-day to 25 weeks).
and was greater than that of birds on the LF
treatment during Week 35, but lower initial pro-
duction levels caused cumulative production to
be lower (Table 5). In a previous report, when
feed restriction delayed the onset of lay, delayed
FIGURE 4. Effects of uniformity and prepeak feeding
program on egg weight distribution of broiler breeder
hens during 27, 31, and 35 weeks. Acronyms inside
legend represent uniformity (H = high; L = low) and
feeding program (T = typical, F = fast increases, and
S = skip-a-day to 25 weeks).

HUDSON ET AL.: UNIFORMITY AND FEEDING PROGRAM
31
cycle length, might have resulted in LS birds
having the best performance of all birds on treat-
ments with L uniformity. Cumulative egg pro-
duction up to 35 weeks was higher for birds
on treatment HT when compared with birds on
treatment LS; hens on treatments LT and LF
produced intermediate numbers of eggs (Table
5). Increased uniformity of sexual maturation
among hens on the HT treatment might have
contributed to increased production. Our data
indicate that peak egg production was numeri-
cally higher in the H uniformity treatment (Fig-
ure 2), and this treatment generally reached 20,
50, and 80% hen-day production at earlier ages
relative to L uniformity treatments (Table 5).
Although nonsignificant, double-yolked egg
production was numerically higher for birds on
the LF treatment (Table 5). It was expected that
rapidly increasing feed allotments would in-
crease the production of multiple follicular hier-
archies and, hence, increase the incidence of
double-yolked egg production [17]. However,
the more rapid increase in feed allotments for
birds on the LF treatment was apparently not
great enough to increase double-yolked egg pro-
duction significantly. In addition, follicle num-
bers for birds on the LF treatment at 30 weeks
of age were numerically, but not significantly,
higher than those for birds on the other treat-
ments (data not provided).
and greater initial egg weights. Hens on treat-
ment LT had the lowest overall egg weight, pos-
sibly because of the decreased weight of eggs
laid initially by heavy hens. Significant treat-
ment effects on egg weight uniformity during
the first few weeks of production may be partly
due to differences in the numbers of eggs pro-
duced by hens on each treatment (Table 6; Figure
2). Even though egg weights of birds on the LS
treatment were similar to those of birds on other
treatments during the first few weeks of egg
production, a low number of eggs produced and
variability in BW might have caused a decrease
in egg weight uniformity at this time. As the
hens aged and as egg weights increased for all
treatments, egg weight uniformity also increased
(Table 6). Although BW was not normally dis-
tributed in the L uniformity treatments through-
out the trial (Figure 3), a normal distribution of
egg weights was still achieved by hens on these
treatments (Figure 4). Robinson et al. [18] have
indicated that egg weight is significantly greater
in first-of-sequence eggs compared with subse-
quent eggs. Because an individual hen may lay
eggs that vary in size at a given age, differences
in BW may not have adverse effects on egg
weight distribution. According to Wilson [19],
light hens are expected to lay small eggs, and
heavy hens are expected to lay large eggs. Be-
cause average feed allotments were probably
more than required for light hens, this might
have led to increased egg weight for these birds.
Allotments were probably relatively less for
heavy hens and might have resulted in smaller
egg weights caused by increased energy needs
for maintenance. This effect of feed intake on
egg weight might also have led to the generally
normal distributions of egg weights.
When analyzed at different ages, there were
significant treatment effects on egg weight only
at 33 weeks of age, but when analyzed for cumu-
lative egg weight to 35 weeks, there were sig-
nificant treatment effects (Table 5). Hens on
treatment LS had the highest overall egg weight,
probably because of their delayed onset of lay
C
ONCLUSIONS AND
A
PPLICATIONS
1. Higher egg production observed for birds on the high uniformity treatment may be attributed
to similar ages at sexual maturity among the hens.
2. Providing faster than normal increases in pre-peak feed allotments to nonuniform hens improved
uniformity and stimulated early egg production but also led to greater BW and numerically
lower egg production during peak.
3. Prolonging S feeding of nonuniform hens resulted in a delay in the onset of lay, low cumulative
egg production up to 35 weeks, and increased average egg weights. However, weekly egg
production recovered by 30 weeks.
4. Although BW distribution may not be normal, a normal distribution of egg weights may still
be achieved.

32
JAPR: Research Report
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