Even though they may be titled dogs, they still might not be of high enough quality for breeding stock. She should have one litter before she's spayed. There is absolutely no medical or psychological reason for this old wives tale. Veterinarians who still give this advice are behind the times. Find another vet.
Good homes have a way of evaporating when the puppies are born.
It takes a lot of experience to be able to evaluate a potential owner, and could give rise to some awkward situations should careful reflection make you decide this person would not be a good home for your puppy. There are many fine people already breeding quality bloodhounds. If you're serious about getting involved in breeding, we urge you to seek out an experienced breeder at a dog show or through magazines like Dog World and learn all you can. Join the American Bloodhound Club and a regional chapter, attend some National Specialties, purchase a show quality puppy, finish a champion, and above all - talk to other people who love the breed. Study the breed standard, study pedigrees, look at dogs in the ring.