Hi, I've never heard anyone breeding an F1 back to a Lab, breeders just don't do this as far as I know of. All the breeders I know would take the F1 and breed back to a non related Poodle or F1B. Breeding back to the Lab would make the chance of Shedding and Dander greater. Maybe someone else can add something it's just not anything I've ever heard being done not to say it doesn't happen.