On the subject of Yogurt and chickens - "Birds are lactose intolerant" - blanket statements mean nothing. Show me the science.
For example: I believe there is a study out there (my boss claims to have to have read it) that states that all people over the age of 18 are lactose intolerant and shouldn't eat dairy. Dairy doesn't make me sick, but my little sister gets severe stomache cramps if she eats dairy. So because she gets sick and is lactose intolerant, every one is lactose intolerant and I have to give up ice cream and cheese on my pizza?! Good luck with that!
My irish setter loves yogurt, and I let him have limited amounts of it. About 2 ounces twice a week, it seems to help his digestive system. When he gets yogurt regularly, he has alot less gas and his farts are not as bad. And man, can he fart!
My black lab gets diarrhea when she eats dairy - so she just gets to lick the spoon. Can't give to one and not the other and I haven't seen any reactions to the little bit she gets off the spoon. Give her a stick of string cheese and it's squirts-ville.
Obviously my lab is lactose intolerant and my setter is not.
Could it be the same way with birds? you know, some birds are and some are not lactose intolerant. Start with just a little bit, and if the chicken doesn't react negatively to the yogurt, I say let her have it. Good source of protein and possible advantage of probiotics. Just watch for negative reactions, and if she gets diarrhea, stop giving her yogurt. So many people here give their birds yogurt, that should be some indication that not all birds are lactose intolerant.
TO THE OP:
Good luck with your bird. I am glad she showed up!
I'm sorry you have to re-home her. That must be tough. Hope you find a good home for her!