He shouldn't really be shedding or losing a "baby coat". So, you should take him in and have him looked over very closely - ears, armpits, belly, between toes and toe pads, neck etcetera. I would def. have a skin scraping to rule out mange since he's still under a year. They should check for mites as well.
What are you feeding and is digestion okay? Bc if this continued, I'd possibly think about malabsorption as hair loss is a symptom of malabsorption, but it's probably not the first thing I'd think of here.
