How do You Train Homing Pigeons?

I train mine by purchasing healthy birds in pairs. Then I bring them home and shut them up in a coop all by themselves, but I make sure that my other birds can see and interact with them through the cage. I leave them in the coop for at least two weeks and then you set them free. I have had a set or two take off and never come back but most of mine come back after I release them.