First off, this is not a jab at anyone.  Ultimately what you want out of your hunting dog is up to you and the harsh realities of many places in the US, is that there is not a large enough population of wild birds to give a pup enough bird contacts for proper training.

I've come to the harsh realization that pen raised birds do more harm than good for pointing dogs training.  Like most people for many years the majority of birds I have shot were pen raised birds.  Don't get me wrong, I'd get plenty of time on wild birds but more often than not it was much easier and cheaper to shoot 20 birds a weekend at the preserve than drive 6,10, 12 hours away, stay in a hotel for a few days and chase wild birds and come home with five or six wild birds.  I was fortunate and recently moved to an area that has great wild bird hunting of multiple species with reasonable drives.

I purchased a very good started GSP last year and a Brittney pup as my oldest GSP has arthritis really bad and she is officially retired.  The Brittney has pica and while I've resolved myself to keeping him I'm not going to put thousands of dollars of birds into him.  My Started GSP had a steady diet of pen raised birds last year, sometimes 30 a week from Jan-April, my Brittney got very little field time and was relegated to scratch hunting.  I was excited.  His points were solid, he worked birds well, wasn't crowding. etc...  September comes and grouse season opens.  I expect some somewhat of a learning curve, we haven't seen a bird since April, scenting conditions suck, and it gets warm quick.  I watch both make predictable mistakes but as the season progresses the Brittney is finding and pointing most of the birds.  The GSP is finding some birds but missing a good number of them and bumping most of the ones he finds.

My initial thoughts were, some dogs just aren't grouse dogs.  Maybe he's just going to be a pheasant and sharptail dog.  Opening of MN pheasant and my trip to SD disproved this theory.  By now I'm into early Nov and have hunted all but two days since the end of September and the untrained Brittney is a solid dog on grouse and pheasant and my star pupil is a dud on all but woodcock.  I had resigned myself that this dog wasn't going to work out for me, bought a ES pup, and was already lining up a good home for him with a friend of mine that wanted a family pet but did some preserve hunting.

It wasn't until my second SD trip that the light bulb came on.  The land we had permission to hunt borders a preserve where they release birds.  On our first hunt earlier in the year the slough was too deep to hunt the land bordering the hunting preserve, by our second things had dried up and my GSP was on fire except he was missing the occasional bird my Brittney would point.  Then it happened...I had one rooster in the bag that my GSP had pointed perfectly with a clipped beak (pen raised bird) and my Brittney locked up on a rooster that my GSP was totally oblivious to...I downed that rooster and it had huge spurs, nice long taile feathers....clearly a wild bird.  I had put him on so many wild birds that my GSP was searching for a scent cone that just didn't exist on wild birds, the Brittney, not knowing the difference just learned to find birds.

Enter my English setter.  This dogs only exposure to birds has been quail wings.  I do think this dog is an exceptional dog but two days into hunting grouse as a 5 month old pup he was holding point until the flush from 15-20 yards back on grouse.  Same thing out west on pheasant, a few days of bird contacts and he had figured out when to point and even how to cut off running roosters.

By the end of the season both the ES and Brittney were absolute rock stars on wild birds and while my GSP as shown signs of improvement he's nowhere near their level of competency.  I really think I've ruined a good dog by putting him on too many pen raised birds and I'm not sure I'll ever be able to correct my mistake.

I brought my GWP to Maine to hunt grouse this year. We were absolutely schooled

He does wonderful on stocked pheasants, all I have available here

I suspect you are right

Too much exposure to pen raised birds causes lots of bad habits, like creeping.

But not not smelling birds. Some dogs just have better noses.

Also, wrt wild birds vs pen reared, wild quail and pheasants are usually found in different cover, typically heavier cover. I’ve seen a lot of dogs with pen raised experience but not much wild bird experience ignore or be unwilling to hunt good wild bird cover.

It’s not the smelling of the birds thats the problem, it’s the scent cone that indicates that bird is in range to point.  That cone is significantly smaller on wild birds.  Heck, even a human can smell the difference between a pen raised and wild bird.

My dogs were pointing those pen raised birds in SD that were escapees at the same distance.

There are a lot of trail running dogs, that’s been one problem I’ve been fortunate not to have with my lot.  Even my problem dog is a good cover digger.

If possible, now is the best time to train with pen raised .
If you can, only release hens .
Even pen raised birds loose their scent when brooding  
Worked well for my English Setters.