Even with the blinders? Will they kill each other ? And I plan on reducing my cock birds for sure , there a few buff and cinimons I want to single out so they don’t die, and put them in pairs or trios, but have them be the only cock birds in those pens, I was hoping to do 16 hens and 2 cocks in the 8x12, but aparently I need to rethink that strategy, dumb question, but I’m curious, what size pens does a normal breeder use, and how many birdsEven a 20 x 20 enclosure is too small for that number of birds. The 8 x 12 pens are big enough for a pair and maybe a trio but no more than that....come spring the cock birds will start displaying and wanting to mate with the hens, if you have 3 or 4 cock birds in that enclosure (20 x 20), you will wind up with only one and possibly none, it will be a total blood bath.
Ring necked pheasants, in general, are very territorial and aggressive.
Not trying to discourage you from raising pheasants but you need the proper habitat/space for that many birds. I would consider reducing the number of birds you want to raise and concentrate on quality and not quanity.