Table 2.

Body weight (back-transformed means ± SD) between D0 and D40 for control (C) and on-farm hatched (OH) chickens (in grams). Until D29, a sample of 50 chickens per pen was weighed. At D33, 280 thinned chickens were weighed per pen, and at D40, all remaining chickens per pen.

Age	Control	On-farm hatched	P value treatment
Day 01	44.41 ± 3.30	48.79 ± 2.16	<0.05
Day 1	55.15 ± 1.38	59.30 ± 2.49	<0.05
Day 7	196.1 ± 6.8	209.5 ± 13.0	<0.05
Day 21	1,056 ± 26	1,090 ± 35	<0.05
Day 29	1,795 ± 60	1,834 ± 49	ns
Day 33	2,088 ± 48	2,138 ± 57	ns
Day 40	2,729 ± 55	2,792 ± 65	ns

¹Body weights of 50-day-old chicks per pen, measured 2 to 5 h after placement of C chicks. Note that these were different birds than the ones used for dissection (Table 1). The latter sample was measured on placement of the C chickens.