I don't have snakes that large, but I only keep a certain number of chickens so if one goes broody, the resulting chicks get tossed to the snakes. When
TSC sells chicks I'll buy them for that purpose as well, since they're about ten times less expensive than other food sources. I do kill them before feeding, though . . . my snakes aren't efficient enough at killing for me to be comfortable with live feedings, and I'll admit to being very disturbed by the cheeping that occurs when the snake gets a bad hold on the chick. I had a chick go after my snake's eyes, once, too, so there is a danger in that.
I have several different friends with large snakes, and they gather up all the free roosters they can find on craigslist. Most of the time, though, they all feed their snakes turkey legs, which are about the cheapest meat you can get at a grocery store. The snakes do well on it, and you don't get screaming fits from people who don't understand how the food chain works when they ask you what you feed your snake. Of course, most of them had to train their snake to take a leg by feeding a rat and then placing the leg in the mouth while the rat was being swallowed. I know at least one person's snake took to it immediately, but for others it would take a few feedings before they got the idea. I don't know whether there's more meat on a turkey leg or quail, but I guess for me it would come down to which is cheapest.
None of these snakes have issues eating mice or rats when those are offered, mainly, I suspect, because their natural diet is composed mostly of mammals. The only issues I've ever seen with a snake going off of rats or mice when offered a different food is when the snake species in question is one whose natural food source is something other than mammalian, such as snake, toad, or bird eaters. I wouldn't worry about it unless you have a bird eating species.
I have noticed that when fed chicks, my snakes' poop smells worse. That's the only fault I've found with it, and it's something I can certainly live with.
