I have always used quail, because of predictability, cost, and last but not least I hunt quail. I don't hunt pigeons, pigeons are not hunted in the manner of upland birds, so I shy away from those with pointing dogs. Retrievers seem to be fine working pigeons. I would have no hesitation to train on pheasants, initially with some precautions to protect a young dog from spurring. The dogs only respond to spurring 2 ways, one it makes them mad and they learn to grab from the back, and sometimes break their back, or two, they become bird shy of pheasants, creating a whole new set of problems, which are very difficult to resolve. It's usually softer bitches that have issues.