Always run your pup in places where wild birds reside.
I totally get your point and the reasoning, and that makes me want to move to Montana. Ability to find wild birds simply for gun conditioning your dog. Not possible for much of the country.
You can make fair wages and have a reasonable cost of living, or you can live in Montana.
Why would you own a bird dog if you live in a place with no wild birds?
We have wild birds, but getting into chuckar is a lot harder than walking up pheasant, Huns, and sharptails. Finding quail is a great training aid, however. Unfortunately most are on private land with many close to or in towns.
So, it's planted birds for the most part. I wish I still had my Montana house.
As to gunfire training, after I transition from banging pots and shooting cap guns I cut off shotgun shells at the top of the brass and shoot off the primers in guns we'll be using in the field. I just pop out spent primers and put new ones in.
