We have lots around our property, including one that shades the coop. I did see somewhere that the wood is fine for chickens (coops, roots, etc), but my Beloved Husband has also been tossing the leaves to the girls, and they gobble them up. I haven't seen any adverse effects, but since my middle name is "paranoid," I thought I'd ask the experts here ;-)
This is the tree I'm talking about: http://en.m.wikipedia.org/wiki/Ailanthus_altissima
This is the tree I'm talking about: http://en.m.wikipedia.org/wiki/Ailanthus_altissima