You get some nice breasts and broad backs from starting with Cx as the base. There are some that are just skawny losers. Sometimes it is simply that they are not competing well for food or just don't thrive or throw back to something from the non-Cx side. Get that from any breeding. That is what the stock pot is for. I have a lot of stock, but it is tasty so no loss. I have not had any inherit the self destruct gene from their parent Cx. That is a real bonus.
I have not eaten the ones that are large breasted as they go back into the breeding program. I won't know how their genes really carry through for another year, but whatever their genetic background is, it is very compatible when combined with just about anything. I am looking for for a sustainable DP bird that is big and can take care of itself without excessive input from the government or needing to be purchased from a hatchery. Cx here come with a paper that must go to the processor with them.
The breeds that were known as being good DP have mostly been ruined by indescrinimate breeding and are no longer up to their original breed type. The genes are still there but the gene pool is getting too small. Time to make a new gene pool in my oppinion, with the best of whats left or spend lots of money feeding lots of chickens in order to get those few that are up to scratch.
The problem is that in the case of Cx, you must be willing to purchase and feed a group of them without special treatment letting them be chickens without coddling them. You must then check them pretty regular to catch the ones who want to die on you and get them into the soup pot ASAP. This gets expensive if you don't catch them in time,the dog eats chicken a lot too, but I am learning to know which body type of Cx has the best chance of going forward, so that helps. The feathers are a good indicator as well. I chose to cross them with chantecler and buckeye because they have some pretty good traits of their own; decent breasts, no combs and cold hardy that I want to continue with.
I want to encourage the OP to try this with her own preferences for crossing with the Cx, as it really has potential. I really don't think you can go wrong if you cross them with any breed that used to have a reputation as a meat bird pre-Cx times.