Some of the best sustainable meat birds are Sussex, Marans, Bresse and New Hampshire. Those would be my suggestions for anyone looking to raise meat birds that can breed naturally and will breed true. These will mature more slowly than a Cornish X but they are all very excellent table birds and will lay well too. I would not expect them to go broody and raise their own chicks, but it's possible. I think any of those breeds would be a great choice.
We raise a line of Hmong meat birds that aren't purebred. They are dark skinned, so not to everyone's taste. They mature relatively quickly and the hens do go broody and raise their own chicks. I did not add them to my recommendation list because they aren't commercially available. If you're looking for something similar, maybe try to find someone who has Ogye Yeonsan.
We raise a line of Hmong meat birds that aren't purebred. They are dark skinned, so not to everyone's taste. They mature relatively quickly and the hens do go broody and raise their own chicks. I did not add them to my recommendation list because they aren't commercially available. If you're looking for something similar, maybe try to find someone who has Ogye Yeonsan.