Feeding activity in groups of newly hatched broiler chicks: effects of strain and hatching time

The feeding activity of 2 strains of broiler chickens was investigated during their first week of life in relation to their hatching time. Fast (Ross 308) and slow-growing (LB) strains were allocated to 1 of 3 (early, middle, or late hatch) single-strain groups of 80 to 100 as-hatched birds in 4 replicates divided into 2 time-separated blocks. Behavioral observations differed between blocks and were carried out at intervals on d 1 to 6, and the percentage of birds feeding (from trough or paper), drinking, or being otherwise active (block 2 only) were registered. A higher mortality caused by flip-over was seen among the late-hatching birds from the slow-growing strain. The percentage of birds engaged in feeding activity was similar for the 2 strains, but LB birds began to eat from the paper later and were observed eating from the trough less than Ross 308 birds, which in turn were less active than LB, especially in the early and middle hatch groups. Early hatch groups were observed feeding from the paper more than the middle and late hatch groups. Drinking behavior mirrored feeding from the trough, indicating that drinking was prandial. Within strain, no effect of hatch time was found on live weight at hatch, but the feeding behavior of early hatched birds led to a small, transient weight advantage on d 3 after hatch. The transition from feeding on paper to feeding only from the trough may have less effect on birds that feed from the trough sooner, such as the fast-growing strain.