I have three chicks in the brooder right now. All three have been fine up until today. They are two weeks old and growing fine. They are on medicated chick crumbles and they have plenty of water and they are warm enough under the brooder lamp, but I have been raising the lamp each day so they are not too hot. One chick is laying down, won't walk and has both wings splayed out to the sides. She won't walk no matter what and she seems to be holding herself upright with those splayed wings. The other two are just fine. She's not pasted up either. What could be wrong with her all of a sudden?