By the time the next breeding season roles around you'll have had a long enough quarentine that if any illness is lurking around you should see it.
One issue is you don't know their history, so you can't tell the people you sell the offspring to what their background is. Hopefully this won't be a problem, it all depends on the person you sell to and what their purpose for the animal is. As long as your honest and produce good quality, healthy animals, you should do fine!