Hi. You've barely given any information.
1. How old are they?
2. What are you feeding them?
3. In what kind of kennel situation are you keeping them?
You say you've bleached down their area, like it's a novel thing to do. I typically bleach pup kennels at least twice a week, if not more, depending on how many pups/weather, etc.
Your pups could be losing hair simply because of living in filthy conditions. Or, you can be doing everything right, and they simply do have hereditary mange.
Can't know which, until I see pics of the kennel, and have these questions answered.
Jack





