This mushroom is a polypore, meaning they disperse spores through small pores (holes) on the underside of their caps.
The different species of the chicken of the woods mushroom are both saprotrophic (feeding on dead trees), and parasitic (attacking and killing live trees by causing the wood to rot). Whatever their method of feeding, you'll always find them growing on or at the base of a living or dead tree.
Chickens are easily recognized by their large clusters of overlapping brackets, and bright yellow-orangish colors. The colors fade as the mushroom grows older.
Many polypores are also medicinal mushrooms, although there hasn't been much research done on this one.One study has indicated that it inhibits bacterial growth.
Other names are chicken fungus, chicken mushroom, and sulphur shelf. The genus isLaetiporus.