Sorry about the newbie question here. I got my first chickens 4 months ago as adult hens. I started with straw as the bedding material, but have not been happy with it as it is not very absorbent. I decided to get a bale of pine shavings and toss it on the top of the straw. I tossed some here and there in the spots that needed it most, but when I go back to the coop it seems to be gone with only the straw remaining. This has happened 3 times now. Could the chickens be eating it, and if so, is it harmful?