Fig. 2.

Periods of cage protection and coprophagy in Japanese rock ptarmigan chicks. Three broods, with their hens, were protected in cages from 27 June to 20 July, 2016. Black dots indicate actual or estimated chick hatching dates. Gray bars indicate the period of cage protection. Black arrows indicate observations of pecking traces on the cecal feces of the hens. Coprophagy started before the first excretion of cecal feces by chicks because cecal feces were not excreted by chicks until they were 4 or 5 days old. Coprophagy ceased by 3 weeks of age in all three broods.