More on Ferret Neck Biting

Question
I have read all i can find on ferret's biting the necks of others. I have had our ferrets for 3 years, we rescued them. There are three, 2 males and one female. They have always played rough and been active. Upon the female losing most of her hair this year and the older male having shorter daily playtimes - we began noticing the younger male showing dominance and playing rougher and rougher with the other two. It is now to the point that they cannot have playtimes together as he will drag them around until they have wounds, he only chases them down and will not defer from any other activity anytime he is introduced to them again. He will even do this in the hammock at night, we'll wake up to the others squealing - i have tried training and sitting in there day after day after day working to get him to stop, it seems to be an increasingly obsessive behavior at this point. Is there a reason for this NEW behavior after 3 years of them all being together and a way to stop it? I have them seperated now,and miss how they all played together before  - when playtimes were active and noisy and fun. Thank you

Answer
Hair loss and sudden aggression are both signs of Adrenal Disease and if they are older than 3, this is very likely.  Get them to your vet and begin the treatment for adrenal which is either surgery or medication depending on your vet and their ages/health.