I train my own dogs to hunt with me. The dogs I buy, I keep.
Not a professional trainer that has to deliver a trained dog at the beginning of the hunting season ... so my comments are limited to those that want an effective bird dog companion that you trained yourself.
I am also not training a bunch of dogs at once. So if I was training dogs for a business ... I get that pigeons are the most cost effective "tool" in regards to birds.
I have found little need for a lot of birds over the summer and find some dogs (through observations with bird dog clubs) that are trained on pigeons almost react to the situation as a training game ... also all that chlorophyll in the summer grass hides scent and dogs seem to get too close to these planted birds. The scent cone of planted birds in the summer is small.
I prefer to work on retrieving, obedience, whoa, etc... in the summer.
I really like chukar for working young dogs across the entire fall and good for refreshing even the oldest bird dog.
What is a professional trainer charging these days ... 100 - 200 per week. Put have that money (or what you can afford) into a fund for preserve chukars. Have them planted where you know they are or plant them yourself ... use the check cord ... have a friend shoot ... if they miss ... chukars usually don't fly that far and follow ups are more like wild birds ...
I would rather put my dog on many birds once every week or two, than a pigeon every morning.
Just my opinion, but I have been hunting over Britts for almost 35 years and they all do (did) a pretty nice job in the field and woods.
Wild birds are great to train on when allowed by law. Many of the big name pointer trainers go to the Dakotas and Prairie Canada in August ... training on wild prairie birds with their dogs and a host of client dogs.