Pigeons sometimes get sick even in the cleanest lofts. Sick pigeons often ruffle their feathers and look droopy. When they are sick, they often have watery droppings. Many different diseases will cause these symptoms. Asking an experienced pigeon flier for help is a good idea. If you have no one to help you, it would be a good idea to remove the sick pigeon and place it in a small pen or cage. This may help to prevent the disease from spreading. You can call one of the pigeon supply companies for help.
Pigeons also may get lice. They live on the pigeons and in the cracks in the loft. Dusting powders and roost paints will get rid of lice. The lice and miter drink the pigeons blood and chew on their feathers. Dusting your birds several times a year will get rid of the lice. A handful of Borax laundry detergent in their bath water also helps remove and prevent lice. Dusting powders and roost paints can be purchased from any pigeon supply house.
The bottom of the aviary should be made from wire. The wire should have a small size mesh because pigeons will not walk on it if the mesh is too large. The mesh bottom allows the droppings and rain to fall through it.