My chickens are pecking at each other and they r losing all types of feathers. They have sores on there back end and some by there wings. I included a picture of one of my chicks that has lost lots of feathers. We do not know what is going on or why. We have checked for mites and lice and have found nothing. We have seperated a few of them to c if it was them doing it but the other chickens have just gotten worse. Please if anyone can help it would be apreciated. Thanks all.