British poultry science vol:49 issue:2 pages:222-231
1.A total of 1200 Cobb broiler breeder eggs were incubated under either standard conditions (C group) or high CO2 levels (CO2 group) during the first 10 d of incubation. The CO2 level of the CO2 incubator was attained gradually by a natural build-up of CO2 due to air-tight closure of the incubator. From d 10 of incubation onwards, all eggs were incubated under standard incubation conditions. At d 18 of incubation, the eggs of both incubation groups (CO2 and C group) were either injected with water-soluble dexamethasone (DEXA group) or with saline (09% NaCl; saline group) or were not injected (control).