A great many of the birds at the store are roosters. They're just 6 week old roosters. (fast growing breed)
As far as your home raised excess roos go, yes, of course you can.
The breast meat is usually fairly tender even in an older roo, but not the rest. You can take out the breast to fry, (without the skin if it's leathery) then crock pot the rest and make BBQ sandwich meat, or dumplings, or whatever. I use a lot for burritos, enchiladas, etc. I love the flavor of the older birds, and the dark, rich broth. It stands up well to any seasoning.
It helps to brine it before you cook it, by soaking the meat overnight in a brine solution. I use about a tablespoon of salt per gallon of water. An equal amount of sugar cuts the harshness of the salt.
You can boil or crock pot a cut-up bird until tender, then arrange the pieces in a baking pan, and add BBQ sauce or some other sauce or gravy, and brown in the oven. It'll be delicious.
They can also be pressure canned, and you'll have home canned chicken, which is so much better than that bland, mushy stuff from the store. Any pressure canning book will tell you how to do this.
Enjoy your home-raised meat. With a little experience you'll find which methods of preparation suit your tastes the best.