The chicken has now become the first bird to have its genome sequenced.
Direct descendants of dinosaurs, birds diverged from our own ancestors more than 310 million years ago. The chicken genome is only about a third the size of our own, but contains approximately the same number of genes. About a fourth of the chicken's base-pair sequences are similar to those of humans. These genes are most likely associated with function rather than form.
By function, of course, I don't mean hen parties, playing chicken or crossing roads. I'm taking about the basic chemical machinery of life that lets an adult creature develop from a single fertilized cell, and then maintains it (more or less) intact for the allotted number of years.