When do I I put my chicks on all flock? My older two chickens are on it already and they are around four months old- four and a half months and my young ones are nine weeks. They look to be growing well and are very active. They live with my silkies so it's harder to separate the food whenever the chicks are about as tall as my hen. Also I wasn't sure if my hen was small/undernourished because I planned on showing her. Chicks in the back are EE's.