They should get bigger as they get older but given that they are heritage birds and not Cornish cross (grocery store chickens), they will NOT get as round and fat as them so if that’s what you’re expecting then you may be disappointed. They also take longer to grow out. More like 4 months (16 weeks) or more as opposed to 8 weeks. They grow slower and don’t get as big but you should still get a decent amount of meat. But don’t be expecting CX growth rates. But even with CX, 3 weeks is pretty young so they still wouldn’t be huge. Just be patient. Don’t give them too many treats to unbalance their diet. Maybe it won’t matter since you’re butchering them anyway but too much fat probably won’t taste very good anyway. You could possibly try meat bird feed though if you wanted to. It might help. But do not expect CX growth rates or size. Heritage take longer. But they also taste better from what I’ve heard. Good luck.
Yup! Exactly!Key point.
Even at 16-20 weeks you're going to get smaller, skinnier birds with less breast and more thigh than a Cornish X. They just don't have the genetics to achieve that round, full, double-breasted shape and they aren't going to grow with anything like the speed of the Cornish X.
They'll be awesomely tasty though.
