Flock uniformity (%)
Bodyweight (grams)
PHOTO: MAXIMILIAN VON SAURMA-JELTSCH
Feed Amount (g)
Bodyweight (lb)
In many coun- tries the availa- bility of labour limits the ability to undertake gradings. With no gradings, pens are not used in the rearing house.
very important to develop the frame and foster uniformity, which means the recovery of small and very small birds is im- portant. Without the pens in rearing, small and very small birds cannot be recovered properly, and frame uniformity af- ter 8 weeks of age will be poor. This is especially true for breeders that come from young grandparents. A grading or sorting at 4 weeks of age of the smaller flock members (10- 15%) and recovery by 6 to 7 weeks in bodyweight (frame size) is important to maintain uniformity. This same concept is valid for both males and females and means only one early grading is needed under certain conditions. Consider doing one grading at 4 weeks of age when uniformity is below 65%
during rearing. 2.800 2.600 2.400 2.200 2.000 1.800 1.600 1.400 1.200 1.000 800 600 400 200 0
0 1 2 3 4 Automatic Scale Weights 5 6 7 8 9 Manual Scale Weights 10 11 12 13 14 15 16 17 18 19 Age in weeks Bodyweight Standard Average Bodyweight (lb)
Figure 3 – A graph showing the uniformity curve of a parent stock flock and weekly feed allocation. 80
70 60 50 40 30 20
0 1 2 3 4 Weekly Uniformity-Av. 68% 18 ▶ POULTRY WORLD | No. 7, 2022 5 6 7 8 Feeding curve 9 10 11 Age (weeks) 12 13 14 15 16 17 18 19 20
115 105 95 85 75 65 55 45 35 25 15
20 21
at 3 weeks of age. This may occur when chicks are small at re- ception and when management is suboptimal in the first week. In larger chicks at 1 day of age, where uniformity is above 65% at 4 weeks of age, grading is not needed if the equipment and management conditions in the rearing house are correct and properly managed (i.e. feeding, watering, ventilation, litter conditions). Figure 3 shows a uniformity curve that is below the target of 80%. It is important to note, however, that fluctuations in the uniformity curve are not drastic and fluctuate between 65-75%. The data indicates that – with consistent feed intake – uniformity should not fluctuate by more than 5-7% from week to week.
Expertise The shortage in farm staff is compelling many companies to use more mechanical devices or automation. In the process, it appears that these devices give more consistent results for flock performance. However, controlling and maintaining the equipment is a very important aspect of flock management. For this reason, farm staff need to be more technically trained to ensure that the equipment is operating correctly and indeed delivering solid data.
Figure 2 – A graph showing weights of birds collected with automatic scales and manually
6,0 5,0 4,0 3,0 2,0 1,0 0,0
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