Hi there! I'm basically just going to agree with what's already been said, but because you asked and I was interested I went ahead and ran the numbers:
Cornish Cross:
- 2.55$/ chick
- 8 wks/ 6 lb
- 2 lb feed/ 1 lb meat
- Conservative mortality rate 1/ 10 chicks
- 3 sq feet/ bird
Heavy Breed Rooster:
- 0.75$/ chick
- 18 wks/ 6 lb
- 6 lb feed/ 1 lb meat
- Conservative mortality rate 1/15 chicks
- 6 sq feet/ bird
Now, if complete accuracy is very important to you, I'd recheck these, but these are averages I've heard. I know for a fact that CX have a very nearly 2:1 weight ratio, although I just eyeballed the figure for the roosters based on past experience. Keep in mind that if the heavier breed roosters are dual purpose birds, they'll be much more inclined and able to forage for at least a portion of their own food, especially as they get older, whereas CX will be almost entirely reliant on what you purchase. Also, because the heavy breed roosters you're considering will live longer and be more active, I allotted them more space; and if you have a sizable enough pasture, I'd recommend even more than that. I mostly factored in mortality rates because they have been such a point of contention when it comes to CXs; if the roosters are really dual purpose breeds tbh I'd expect a much, much lower mortality rate than 1/15, but I thought I'd play it safe (for the record, the CX mortality rate is lower too, I'm just going with the highest figures for posterity). Now, this is already looking like it has a fairly apparent outcome, but I'll continue regardless
(also, you mentioned carcass quality. I know that CX dress well, but I have heard from people who prefer the meat of dual purpose birds and foragers because it's less fatty and more flavorful. I don't know how much of a difference it actually makes, but if that would really matter to you it might be something to look into)
Now, I don't know how many birds you'll be raising, but if it's on a smaller scale like mine then you might go with, say, Purina meat bird grower, which is 16$ for a 50 lb bag. Each CX chick will then theoretically eat 12 lb to dress out at 6 lb, but let's play it safe and go with each of your CX will eat 15 lbs of food before slaughter, or about 5 dollars worth of food. In contrast, to get to slaughter a heavy breed rooster will eat ~35 lb of food- even if we round this down to 30 each bird will still consume about 10 dollars worth of food- twice as much as a CX.
You can manipulate these numbers to more specifically fit your situation, but no matter how you divide it, the extra 1.80$ is more than made up for in food cost alone, even if you factor in the higher mortality rates (then it ends up closer to 5.8:10.3)
Anyway, I'm not sure if this is exactly what you were asking, but I thought it was interesting and it's at least something to consider
{{also please feel free to tell me if I got anything wrong- I'm happy to correct it!}}
