Released birds are not wild. No comparison. It's still a 'canned hunt' in my books. Doesn't matter if they are planted minutes before or days later.
However, it is as good as it can get to train dogs whether a pointing breed or a flushing breed.
I've planted thousands of birds. Spent hundreds of hours training mine and other peoples dogs and judged versatile pointing dogs for 20+ yrs.
Nothing compares to wild.
JW