We have 20 roos that we need to butcher or sell. They range from 4 months to almost a year. They need more meat on them before we butcher. What is recommended to put more meat on them. We keep them cooped up.
I use both at the same time that way the meat is well muscled and good enough fat content to be good and juicey. I feed a high protein game bird feed and straight cracked corn mixed, have had good results fast with this method.
You can butcher them at any age, but usually from 12-16 weeks or so is the most tender meat, and then it gets tougher as you go on--- you can butcher them until they're very old.
It's possible they're as "big" as they're going to get-- if they're not cornish crosses or specically meat birds, you wont' get a huge bird. They're still yummy!!! We've had a lot of rooster stew and rooster pot pies that were out of this world!