Jokes aside, I know that my vet pulls Mimi's skin to check elasticity. I think (I may be wrong) that if there is too much skin (saggy), it means that they are dehydrated or lacking in certain vitamins. I am no expert but I know for sure that for doggies if the skin is too loose it means something ... what exactly, I am not sure. I don't know specifically about saggy boobies especially in a young dog. Is your dog's skin all over saggy or is it just the boobies that are?