How old and what breed?That's what alerted me to the problem, I had not picked her up in a while and when I did she was noticeably lighter. She is also in the process of molting, most of her new feathers are about 1" long. I was feeding her layer pellets but switched to flock raiser since only one of three was laying. I have oyster shell and grit available in separate dispensers. I did introduce a new bird to replace a mis-identified rooster but now that I think about it she has had runny poop since before that. I was not able to completely quarantine the new bird but I did divide the run and gave the new bird her own space, mostly to avoid any over pecking or injury. It was exposed to the other two and I put them all on the roost at night.
-Kathy