chick_magnet, it's unusual for somebody to want tougher birds, but if that's your preference, I'd stick with DP's. They have better flavor. You can prepare a broiler-type, (the fast growing meat birds such as Cornish X) so that they'll be tougher, but no, they won't taste the same. They're pretty bland, compared to a DP. So you can get the texture, sort of, but not the taste. Unless you can keep them alive a lot longer, the older the get, the more the flavor of the meat develops.
mstricer, here's a link about heritage birds, how to cook them. You can have a tender bird, depending on how it's prepared. You can't cook them the same way you'd cook broilers, that's all. If you cook them overnight in the crockpot, on low, they're usually tender by morning, or if not, let them cook until they get tender.