The rooster pheasant pictured above has a blinder on. These blinders are placed on the pheasants when raised in pens so they won't peck each other to death. The blinders are attached thru the pheasants nostrils. The blinders are then removed just prior to release.
Pen raised pheasants have large open nostrils. Wild pheasants nostrils are not open at all.
This is the easiest way to tell if you have shot a pen raised bird or a wild one.
I have heard stories of guys being told that they are hunting wild birds, and then find out later they were pen raised.
Now you will be able to tell easily yourself.