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Abstract
Delay in access to feed for 1-d-old chicks impairs posthatch growth. It is a standard
practice that 1-d-old chicks are deprived of feed for about 48 h before they are placed
on farms. During incubation, there is a spread of 24 to 48 h for late versus early
hatching. As spread of hatch increases, number of chicks that are feed-deprived for
a longer time before free access (IA) to feed and water increases. In this current
study, we investigated the effects of time delay in feed access on chick juvenile
relative growth (RG: a measure of speed of growth) up to d 7, taking into consideration
the duration of egg storage and spread of hatch. Our results confirmed that delay
in feed access caused weight loss during holding time and depressed growth rate after
access to feed. The magnitude of the effect depended on the hatching period within
the hatching window. It also depended on whether the biological age (BA) or the chronological
age (CA) of the chick was considered. Immediate access to feed produced significantly
different results depending on CA or BA. Both ways, the method seemed to benefit the
late hatchers. This finding contrasts with the effect of delayed feeding in which
early hatchers benefited more. Long duration of egg storage depressed RG not only
of chicks with immediate access to feed but also in those denied access after hatch.
Delay in feed access significantly aggravated the effects of long egg storage duration
on RG. Triiodothyronine levels were lower in feed-deprived chicks, and the effect
was greater in late hatchers. It is concluded that the beginning of delay in feed
access should be determined from the time of hatch not at the end of hatch. It is
suggested that the adverse effects of delay in feed access can be reduced by providing
a source of energy in hatching baskets or during transportation.