Do you have the whites or are they the Partridge?Most heritage Dual-Purpose fowl will do, but if you want meat then I would suggest a faster maturing bird. Examples would be the Chantecler, Delaware, Dorking, and New Hampshire.
I see some mention of the Buckeye, which is a great breed. However, they mature very slowly. The soonest ours where ready for butchering was 7 months. The meat was very flavorful, but extremely tough. It was also mostly leg meat (Buckeyes have huge legs), as the chest wasn't very well developed yet.
We have also raised a number of Chanteclers for butchering, and they are our favorites so far. They mature rather quickly, and have large breasts. We butcher ours as soon as 4 months, but wait till around 5 - 6 months to butcher most of them. They are not a fatty breed (pure muscle) but are very tender, and their flavor is very light. This being said, I have noticed the Partridge develop meat faster then the Whites.