In Canada, the University of Guelph's Department of Animal and Poultry Science examined how feeding might influence egg laying behaviour in commercial broiler breeder hens.
The team conducted a study to determine whether feeding feed-restricted broiler breeder hens during the sitting phase of nesting results in a higher incidence of floor eggs and/or retained eggs.
They report randomly assigning 60 broiler breeder females (Ross 308) to 6 deep litter pens containing 10 nest-boxes. At 35 weeks of age and for 9 weeks, the researchers say, feed was distributed to all pens at lights-on every second day (fed normally, FN). On alternate days (feeding delay, FD), feed was distributed when two to three hens per pen were sitting in a nest box.
At 41 weeks of age, behaviour was sampled for 26 days. i.e. eggs and egg location data were collected daily, and eggs were scored for extra-cuticular calcium.
Of 81 instances in which the hen was sitting firmly in a nest box at the time of feeding, the hen left the nest-box to feed in 80 cases, and in one case the hen laid its egg then exited to the feeder. Of these 80 instances, Sheppard and Duncan write, the hen returned to a nest-box to lay her egg in 58 cases; in twelve, the hen returned to the nest-box but laid no egg; in seven, the hen did not return to the nest box and laid no egg; and in three the hen laid her egg on the floor.
Thus, they found that the mean floor egg percentage did not differ significantly between days with normal feeding and with feeding delay – 13.3 ± 3.2% and 13.3 ± 4.7% – respectively. The mean extra-cuticular calcium score over all pens was 0.9 ± 0.06 on FN days and 1.2 ± 0.06 on FD days. These scores differed significantly, the investigators point out.
In conclusion, they say, feeding broiler breeder hens during nesting results in a conflict between feeding and nesting motivation and higher numbers of extraneously calcified eggs. However, it did not significantly increase the amount of floor eggs, even though nesting hens will leave the nest box for food.
[Source: British Poultry Science, Volume 52, Issue 1, 2011, Pages 20 - 29]