I have 14, 9 week old chicks. 13 hens and 1 Roo. I have one light Brahma girl whose bottom is always a mess. I've had to clean up her bottom with soapy water twice now, and she's going to need washed up a third time. I use ACV in their water, they have pine shavings as litter, and they eat chick starter/grower crumbles. I've trimmed the feathers short back there but she constantly has poo all over her bottom. Her vent isn't clogged it's just where it runs down her butt and builds up. I have no idea why this keeps happening to her. I clean her and she gets all messy again. Can anyone help? I feel so sad for her with matted feathers instead of a cute fluffy butt. Can anyone tell me why this keeps happening and if there is anything I can do to stop it? Thanks.