my 8 month olds girls have been picking each other /themselves. They have missing feather above and below their tails. the area that is missing feathers looks red and irritated .I have checked them bugs I don't see any .I'm also always touching and petting them if they had bugs I would think they would crawl on me too. i haven't seen any on me either nor have i been itchy after being with them. what could be causing them to have this condition?