Delaware, New Hampshire, and some strains of White Rock were developed as meat birds before the Cornish Rock, Cornish X, broiler, whatever you want to call today’s meat birds were developed. That was 50 years ago or more. If you don’t continually reinforce certain traits with chickens by selecting the breeders based on those traits, the chickens fairly quickly lose those traits. Breeders have not been reinforcing those traits for over 50 years. Today’s Delaware, New Hampshire, and White Rock are nothing compared to those bred for meat way back then.
There is more to a meat bird than pure size. How long do you have to feed the bird to get him to butchering weight? How expensive is that feed? Chickens will put on weight faster if you feed them a high-protein feed. A high-protein feed is expensive. There is a balance for what works for you. I saw an advertisement from way back then where the strain of Delaware chicks being sold would hit 4 pounds at 10 weeks, but that required a certain feed regimen.
I’m not trying to put anyone down, I have a lot of respect for people that breed showbirds, but I’m not a believer that a showbird automatically makes a good meat bird. You have to know the breeder. If they are just breeding for show, they are breeding and raising the chickens for what the judge sees. The judge does not see how fast a chicken grows or how much it costs to put that weight on him. They are often fed special diets to get that look, like adding a little vegetable oil to the feed to make the feathers shiny. Some supplement the feed with Manna to really get the protein level up there. If you can find a breeder where rate of growth and efficiency of feed to weight gain are goals, then you will be much better off, but just because a bird is big does not make it a good meat bird.
Teaspoon, how big of a chicken do you need? There are only two of us. We get two meals out of a fairly small pullet. If they are bigger than that small pullet I eat chicken for lunch, maybe once maybe three times. Some people are led to believe that bigger is always better, but is it really?
You can eat any bird of any age or sex, but you need to adjust your cooking techniques to the specific bird. The older they are the slower you need to cook them and you need to provide moisture. I recently roasted a 3-year-old rooster at 250 degrees for 4 hours in a covered roasting pan with just a little water. Delicious. If I had tried to fry or grill him, he would only be fit for the dogs.
Some people butcher their chickens at 12 weeks so they are young enough to be fried or grilled. There is not much meat there. I like to wait to at least 4 months and preferably 5 so there is more meat but I don’t fry or grill them.
Teaspoon, at what age are you going to be butchering yours? Which of those roosters will give you the best carcass at that age based on the way you feed them? If you are going to buy all their feed and eat them young, you might want a different one than if they pretty much forage for all their feed and you butcher them much later. I think that is the type of criteria you should be looking at to decide which rooster you want to breed, what suits your unique situation. The general rule is to eat the ones you don’t want to and breed the ones you’d rather eat.
If you are selling pullets, you will probably get a better price for purebreds or maybe Easter Eggers, especially if they hatch from blue or green eggs. I think an Easter Egger should hatch from a blue or green egg before you call it an Easter Egger. People want a pullet to lay a blue or green egg if you call it an EE. A pullet that hatches from a colored egg has a chance of laying a colored egg.
If you elect to keep your Buff Orps and sell the pullets as Buff Orps, I suggest you get a copy of the Standards of Perfection (SOP) for Buff Orpingtons and at least try to breed to those standards. You’ll find it is not real easy but unless you put some effort into it, yours won’t even be hatchery quality in a generation or two. They do lose those characteristics pretty fast unless you select your breeders for those qualities. That’s why the EE’s may be the best way to go. People will get excited about the colored eggs and there are no standards for EE’s.
Personally I don’t breed my barnyard mix flock to anyone’s standards but my own. I eat the roosters I don’t want to breed and eat the hens that don’t lay the way I want them to. Yeah, I can be kind of anti-social.
If you understand what you are really after you can get there. Good luck!