Chickens were first weighed at 1 week old using a scale measuring to the 0.1 g accuracy. The chickens were then weighed weekly until they were 12 weeks old, and then were weighed again at 14 and 16 weeks old. When comparing weight between hatchery and control chickens, males and females were compared separately to allow for weight differences due to sexual dimorphism.

Eggs were collected daily from the onset of lay and were labelled according to the day they were laid and which pen they came from. Eggs were stored in a refrigerator at 15 °C before weighing. All eggs were then weighed using a scale with accuracy to the nearest 0.01 g.

All chickens were feather scored for damage to feathers, combs and wattles at 19 weeks of age. They were scored on a scale of 0 – no damage to 3 – severe damage, missing feathers or bleeding wounds on five body parts (head, back, tail, underbelly and wings). Combs and wattles were scored on bruising, number of bruises and open wounds. Feathers were scored on the amount of damage and whether any feathers were missing.