It was written by guitarist Jerry Cantrell for his father, who served in the Vietnam War. His nickname was "Rooster."<2> The nickname most likely originated from men who used machine guns (see the second verse, first line) as when it would strafe an area the tracers would make a pattern that looked like a rooster's tail, but there is speculation that it may have been in relation to the 101st Airborne Division, in which Cantrell's father served. The 101st Airborne wore patches on their arms featuring a bald eagle. There are no bald eagles in Vietnam, so the closest thing to which the Vietnamese could reference them was the chicken. They referred to them as "chicken men".<3>
In the liner notes of 1999's Music Bank box set collection, Jerry Cantrell said of the song:
It was the start of the healing process between my Dad and I from all that damage that Vietnam caused. This was all my perception of his experiences out there. The first time I ever heard him talk about it was when we made the video and he did a 45 minute interview with Mark Pellington and I was amazed he did it. He was totally cool, totally calm, accepted it all and had a good time doing it. It even brought him to the point of tears. It was beautiful. He said it was a weird experience, a sad experience and he hoped that nobody else had to go through it.<1>
http://en.wikipedia.org/wiki/Rooster_%28song%29:toast: