We butchered a bunch of excess roosters a couple of years ago. I honestly don't remember how old they were - between 5-6 months, I believe. I also can't speak to the toughness or tenderness of them. I just cook them low and slow so they're always tender. Have you processed a non-cornish cross before? If not, I'll give you a heads-up. They will not be as meaty as a bird specifically bred for meat production. There will be meat, it will be tasty, but it will not be like what you find in the grocery store, nor will they look like miniature turkeys that are all breast and thigh meat. The meat may be a bit more stringy than you're used to. In other words, these guys will have flavor and texture. I didn't get any to process this past year, and I just used up the last one from 2 years ago. I can't bring myself to buy one at the grocery store. I may have to go without chicken until fall....