Hello- I came home from vacation to discover my oldest chicken, Daisey about 7 years has an open sore on her backside ( by her bottom). I will begin to keep her inside and treat her sore with the hopes that it heals. Magots have gotten to it, which I have done my best to clean out and will continue to do so. They are so disgusting... My poor girl. I am hoping someone might have an idea of what would cause this. I was wondering if it a pressure point from being old and sitting too long? A tumor rupturing? Anyone else have this ever happen to their chickens?