We want to spread some powdered lime under the roosting area after cleaning.. below the hay .. wondered if it would be harmful to chickens.. trying to cut down on pests.
It has to be agricultural lime, and yes the powdered kind can be rough on their feet. I buy pelletized lime, costs maybe another $1 a bag, and use it on the litter all the time for flies, odors and moisture. I also don't have to worry about breathing the dust this way.
My roosting area has 6 inches of river sand (ordinary sand) and is very easy to clean. A small amount of sand adheres to the chicken droppings which makes composting better. I use a horse manure fork to clean the chicken manure from under the roost...works great if you can find one with tines close together.
There are a few types of lime that you can buy. What ddawn referred to is ag lime or barn lime. It is nothing more than powdered limestone and is tan to gray in color. It can help to dry up areas, create a non-skid surface, and raises the pH a little, but won't do much for pests. It's basically the fine powder that you'd find on a gravel driveway.
The other type commonly sold at the ag supply is hydrated lime. This is a bright white powder that is mildly caustic. This is commonly used as a sanitizer in barns, it is spread as a sanitizer for floors and can be mixed as whitewash to sanitize walls and wood surfaces. It is caustic enough to actually disinfect areas or heat and dry areas of wet litter. We use it between flocks to sanitize the floor and wooden structures in our hen house. We spread it liberally on the floor and on wooden surfaces in the barn. We broom it in and then cover it with hay before the birds are placed.