Most trainers use pigeons for retrieving work, sometimes for sight pointing pups, to use a showy bird for pups to hone in on. My opinion is, use quail, we actually hunt quail with pointing dogs, where as pointing pigeons is a non-starter. Now retrieving dogs, a durable pigeon can have advantages. If you trap them, with a simple, wire, inexpensive pigeon trap, will work. Almost all pigeons will rehome, you will lose some, here or there, but once they nest in your nest boxes, they are putting down stakes permanently. You will have to "train the birds", before you train the dogs. Find a barn loft or a cleared off space where they gather, use wheat, as a lure. Topeka rail yards had a scad of them when I was through last week. Any areas near railroad and grain bins. Lots of times kids trap them, to sell. You can probably buy them from a racer, he will sell you slower birds. Might not get specific about what you have planned for them! Check out Craig's list. As I said, I abandoned pigeons and went straight on quail 40 years ago. I discount the idea that using quail will make it more difficult to overcome mistakes in training. I think we spend to much effort at assuming the dog's psychology, and underestimating the intelligence of the pupil! Pigeons are filthy by the way, and require more care and more groceries! A lot trainers still swear by them. Good Luck, tell us your experiences.