My husband used to call them bowling balls with legs. I raised mine in batches of 25. I would process them two or three per day. I could not face trying to process them all at once. Mine had feed from seven in the morning until seven at night. I never tried free ranging them but if I had it to...
I wouldn't worry about it. Personally I prefer larger chickens. I don't suggest anyone do this, but the biggest chicken I processed dressed out at 16 pounds. Best "turkey" I ever roasted.