We have six 7 week olds who have recently been given free range with our year-old hens & we have started seeing some emerald green poop. It does not look like diarrhea. Not sure which one(s) have it, but assume one of the chicks as it is smaller volume. There are 2 New Hampshire Reds, 2 Silver Lace Wyandottes, & 2 Ameraucanas.

They are all active & appear healthy. They have access to water in many places around the barn. They all eat starter food, plus whatever they find around the barn that appeals to them. They will also eat the hens' food, which is layer plus cracked corn, but mostly they eat starter/grower.

This may be an idiotic question, but could it be the Ameraucanas? They will lay green/blue eggs when they start to lay. Where does that color come from?