calcimated lime or agricultural lime and DE has the benefit of keeping down smells, moisture, and if ingested works as grit.
I was raised with chickens as a kid and my parents and grand parents used lime they used in the garden for the chicken coop and the yard and put out a pile by the food for them as well. We rarely had chickens die back then, so I doubt it had anything to do from the lime. me? i use the lime as well. i mean really, if people's been using it all this time it can't be all that bad. DE isn't that expensive but for me its hard to find, i have to go about 30 miles to a feed store that carries it, and even then they may not have it in...X_x so I just started to using lime and it works, doesn't bother any of my poultry or fowl.