If your intention is to take all birds to the 7 - 8 week mark before process, then I would not exceed 20 birds. Not so much for bird per square foot, but more for the feeder, and waterer space needed. The birds all want and need access to both all the time because they don't know about taking turns! Good luck with the project.
Good info, thank you folks!
So, it looks like I'll be good raising 50 in a 10' x 10' enclosure, processing the pullets as Cornish game hens at 4 weeks, and the cockerels at 7-8 weeks?
Is it a movable enclosure? I wouldn't want to raise that many on the same ground for all that time, but if you will be moving it around, that is perfectly fine.