I usually trim the feathers back there. I have a white Cochin who is alllll feather. Stuff gets stuck there sometimes. If it's close up against her skin, she gets her backside washed. Otherwise, a couple of snips and its it's gone.My hen has had that happen twice before. Her vent area is crusty and that leads to even more droppings getting stuck. How on earth do I clean it correctly? She’s a healthy girl and I suspect that the cause is only because her droppings accumulated there over a couples days without my noticing.