I have 9 chicks 5 from a breeder that is doing great and very affectionate, and 4 that I got before the 5 from the breeder, they was gotten at a feed store. Well my rhode island red who is the smallest about a few days after getting started looking like it's rear end is white and all around it looks rotten. It won't grow a tail either. It is eating, drinking and acting like normal but it looks gross. Any ideas of what it is and what to do for her? Appreciate it in advance.