Two of the drawbacks I hear folks banter around about heritage breed chickens is that they grow too slowly and they aren't big enough for modern Americans. A lot of farmers and consumers tend toward hybrid birds to get past those drawbacks. (Sometimes gross hybrids, like the Cornish Cross we raised our first year which also make up all grocery store chickens. And sometimes more natural hybrids.)
For the past two years we've been raising Dark Cornish. They do take months, rather than weeks to mature and I can see how that is a draw back. If you're trying to raise chickens for profit, these probably aren't going to be them. Ours mostly free range which means low, low, low feed costs, but it also means greater loss to predators. (Ask me how my opinion of red tailed hawks has changed since my college days as a wanna-be-naturalist...).
I don't understand, however, the idea that these birds don't produce enough meat. I think that is problem of expectations and creativity. A problem we can solve right now. Ready? Think of meat as a condiment...not the whole meal.
A million years ago when we watched "Super Size Me" the thing that stuck with us most is that a serving of meat is about the size of a deck of cards. It changed the way we eat at home and at restaurants (the annoying people that share a buffalo burger at Teds - that's us).
Two weeks ago Bill took two Dark Cornish out of our freezer. For two weeks they've made most of our meals - and I think we'll still be eating them for another week.
The first two meals were shredded dark meat from the legs, which was simmered in salsa and then added to nachos and burritos. Total meals: 2 each for 2 people (aka, 4 meals).
The chicken breasts were made in to chicken parm. 3 meals x 2 people = 6.
Bill made stock from the carcasses and plucked off the rest of the meat. We've had chicken soup at least 4 times each and just made tortilla soup from the stock. There are at least 6 meals of soup left for lunches this week. Some of the tortilla soup was also thickened and used on our breakfast of chilaquiles and again to make Big Bill's Bodacious Blend of Salsa de Enchilada (sauce for 5 total meals of enchiladas).
Side note - we eat a lot of tortilla based meals around here. It's because we have a tortilla press and homemade corn tortillas are the MOST AMAZING THING EVER! (Best $25 you can spend)
So, I think we're up to 31 meals with products from 2 chickens. The chicken wasn't necessarily the main ingredient in many of the meals - in some it was a condiment. But we feel pretty great about this. Processing your own chickens sucks. It's really hard. Knowing that we've gotten so many meals out of these two birds is satisfying.