Chicken's decent, but not nearly as good as beef. It turns out that chicken and its avian and reptilian relatives all share basically the same amino acid profile, which is substantially different from that in human muscle tissue, so a lot less of the protein can be observed and used. It's still better than, say, pasta, which has some protein of its own. Beef is where it's at, when it comes to rebuilding muscle tissue. That and whey protein isolate, but that's a whole different ball of wax.

Sorry, everybody. I used to be really into weightlifting.