Oops! Meant to add that chicken eggs are very useful in research of all kinds. They've used them to study fetal alcohol syndrome and a whole host of other human baby-in-utero related illnesses and defects.
A friend of mine is a Professor at the UW Research labs, and I visit his four huge chicken barns from time to time. He taught me how to hypnotize a chicken, which he does while he's giving some of his lectures. The chicken just lays there at his feet, staring off into space. How much more fun can you have than that? (They'll stay that way for about 30 minutes. They're not real bright...)
My first job out of college was with a mosquito management company. In addition to taking blood samples from wild birds (tested for encephalitis etc.), we would set out chicken coops in the middle of woods and even in cities. We would let them get bitten by mosquitos and then take blood samples and test it. I can attest to the intelligence of chickens- not bright is an understatement. We would 'hypnotize' them by holding them by their feet and swinging them upside down for 15-20 seconds. This made getting blood samples much easier. I only did this for a summer but it took me about a year before I could eat chicken again.!