One of my chicken was really slow and quiet today. She was drinking and eating but she fell asleep while standing up pretty often. Her comb look paler than the other day. The rest of the flock is acting normally. I dont know if its me who see stuff that doesnt existbut i see a small bump at the end of her back/butt(see the picture). Does chicken got days once in awhile that they just dont feel well like us? Somebody got an idea of what she might have? Thank you.