Dick, The percentage now would be all totally stocked birds. Years ago growing up in N.J. Hunted public grounds, which is like preserves, stocked birds. Years ago wasn't bad hunting during the week, with not many people there. Now it is like taking your life in your hands, or the equivilent of being blind and walking the streets of NYC. There were some wild pheasants and quail in some parts of Hunderton County, and it was always fun to hunt them 35 years ago with our bird dogs.
Now live in Pa., used to be a lot of wild pheasants and some quail 25 years ago. Now if you see a pheasant it is a left over stocked one, and I think it is probably on the endangered species list here.
I agree with everyone else about the preserve shooting, not much fun, but if you want to keep a dog and let it get into birds, that is the only way to go.
They still stock some pheasants on game lands here in Pa., and if you get lucky you might pick up a few. Years ago the state of Pa. would stock pheasants when they were 5-6 weeks old, if you didn't post your land, they would let them go in the summer, by hunting season, the ones that lived, were like wild birds. You could hunt all day and have good dog work on birds. Most of the time it was hens, which you can't shoot, but it was good for the dogs.
I like the way Dig said they do it in England. By the time hunting season comes in the birds are wild.
We will see what this season brings here in Pa. I have a English Setter puppy, today he is 4 months old, have him pointing quail that I let loose in the backyard and neighbors field. Hopefully by Jan and Feb I will be hunting over him some preserve pheasants.
:p

David