They do like to make use of dry sand and fine gravel under greenhouse benches for a latrine. I have for many years now left a coarse mesh gate across my open greenhouses in summer. Keeps pheasants out too here.Never lived in a non green environment so can't say about grass but dogs eat it often. Avoid "very loose" fitting collars, with bird warning bells. Found a collar with bell and small skeleton caught on a rusty nail once.
Brian, UK