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Incubation and hatch management - consequences for bone mineralization in Cobb 500 broiler chicks
An incubation study was designed to assess the consequences of hatch time and chick management at hatch on bone ash levels in Cobb 500 hatchlings. Embryos were incubated under either Control (between 37.8 and 38.2 0C) or a Slow start (from 37.2 0C at sett, reaching 37.8 0C at day 13 incubation) egg shell temperatures. Hatched chicks were identified at either 492hrs (early hatch (E)) or >492hrs and ≤ 516 hrs (late hatch (L)) from sett (the start of incubation). The early hatched chicks were then assigned to one of three post-hatch treatments. Early hatched chicks were either sampled early, at 492 hrs from sett (EE), or given access to feed and water for a further 24 hrs (EF) before being sampled at 516 hrs from start of sett. Alternatively E chicks remained in the incubator for a further 24 hrs and were then sampled at 516 hr after sett (EL). Late hatch chicks were sampled at 516hrs (LL). Slow start incubation resulted in a higher hatch rate overall with a larger proportion of chicks hatching late, compared to the Control incubation. The late hatched chicks had significantly higher bone ash than the chicks that hatched early (<492hrs). Of the early hatched chicks, EE and EL chicks had significantly lower bone ash than EF chicks. These results indicate that bone ash at hatch can be improved, either by extending the incubation period, inducing a late hatch, for example by using a Slow start incubation profile, or via the prompt provision of feed to chicks that have hatched early.
AN15343 Accepted 16 September 2015
© CSIRO 2015