Metabolism and Growth of Chickens Before and After Hatch in Relation to Incubation Temperatures

Chick embryos were incubated at 35.8 C from days 1 to 10 and at 37.8 C from day 11 to hatching. Control embryos were incubated at 37.8 C. Other environmental conditions were standardized. Embryos incubated at 35.8 C showed compensatory growth when compared to embryos of the control group and showed a higher heat production (kJ/embryo/hr) expressed as a linear function of dry embryo weight (g) or incubation time (days). After hatching, the compensatory growth of the chickens incubated at 35.8 C (days 1 to 10) continued, as demonstrated by analyses of the weight of the body, liver, and the gastrointestinal tract. The same animals produced more heat per unit of time and body weight. Adult hens from this group showed a trend for higher heat production per unit body weight as well as a higher dry matter content. These results suggest a link between in ovo environmental conditions, growth processes, and metabolic level up to the reproduction period of domestic fowl.