I am curious about how many have or would consider outcrossing to a different breed to improve the breed they're working on.
I'm a relative newbie poultry breeder, compared to most breeders on this thread. So, my opinion probably doesn't count for much. I don't think that it's right to cross breed the old, foundation breeds of poultry in order to improve them. To me, that's not preserving the breed.
I raise several breeds of purebred, heritage livestock, in addition to my chickens. These animals have pedigrees that trace back to the earliest recorded animals of their breed. I'm proud of that heritage and glad to preserve them. Crossbreeding or upgrading has never been allowed. All of these breeds are, or have been critically endangered at some point and had very small gene pools. The stewards of these animals were able to bring them back from near extinction, even when there was only related stock, even with less than perfect breeding animals. If they can do it, why can't poultry breeders?
So, I come to poultry breeding with that mindset. If a foundation breed has had other breeds crossed in, I no longer consider it purebred.
Bob talks about saving old strains that respected breeders have had, once they are no longer able. It seems like blasphemy to their memory, to consider crossing another breed into a long pure strain.
My view on crossbreeding more modern, composite breeds of poultry has been changed a bit. This is due to Kathy resurrecting the Delaware. But even with that breed, I still feel the need to seek out any old strains that might exist and keep them going, for their historical significance.