My point of view as a breeder myself......every time I breed , I want my puppies into the best loving homes out there , I want to make sure (myself)
to know they are in a home with their own families ........I don't see myself turning to a shelter/rescue to find homes for my babies , why is it any difference for the adults? If I think I'm capable of placing a puppy and taking the risk , I should be able to do the same for the parents.
I know that rescues do a lot to find a good home and might get it right the first time or maybe not ( I have seen people getting pets from rescues/shelters, then turned around and rehomed again).
It may take more time to rehome an adult , but I know I'm here for them , providing them with love and care until the last day.