I personally think you started them to early mate, everyone starts them when they think they are ready some young, some old but i tend to wait till there about 7-8 month of age! from what you are saying they are playful (immature), or maybe scared, as i have came across this with some of my mates ferrets. try and approach the hole very slow, even get on your knees, try and pick them up slow aswell that might help! atb brad.