Since no one has answered your question, I will give it a shot. I don't know! lol. I have not raised either breed. It may be difficult to make a general statement. The most important factor would be how the bird has been bred. I just got some hatching eggs from a Barred Rock breeder who bred for meat production, so I am looking forward to seeing what a heritage breed can do in this regard. I do know that the New Hampshires have a reputation for a quicker grow out. Both of these breeds have been used in the broiler industry at different points in the past so the genes should be there to work with. The Farming and Homesteading with Heritage Poultry thread is more likely to have discussions about meat production, with pictures, than the other threads. Good luck and post some pictures of dressed birds if you get some. In my opinion, this is an overlooked, but important part of their heritage.I would like opinions on which is the best meat bird. APA standard bred Barred Rocks or APA standard bred New Hampshires. Which has the fullest breast? I know this is the BR thread but I am sure some of you have experience with both.