Most chins do not like to be handled. Out of 24 chins that i had at 1 time, only 1 was truely hand tame

They're prey animals and flight animals, so don't get too upset when they don't want to be handled, It's their natural instinct
Just a theory about they're fur, has you're vet ruled out a fungal infection?
Is the fur coming out when you hold them? That could be caused by stress. Also, a chin will literally shed patches of fur if they feel threatened. Either that or it could be fur chewing.
I would imagine that moving them from one place to another could be causing alot of stress, and that could be why they won't let you near them.