My friend just got her first ball python, (an unsexed captive-hatched '03) in her store (though he is not for sale yet.) He is much smaller than my '03, perhaps about two-thirds her size. She had him roughly ten days and offered him a mouse yesterday. he just keeps striking in a defensive manner at anything, even people walking by his cage. He struck in the same manner at the mouse (it was whacked but still twitching) and definately seemed more scared than hungry.
He is not underweight at all. She got him from reptile addicts, and they said he had been feeding on live mice. I tried a live mouse also, under strict supervision, and the snake merely struck a few times defensively and then balled up in fear.
My friend is really pretty disappointed in ball pythons, and I feel bad because they can be such great snakes. She just happened to get a "dud" who is pretty nasty, in her opinion. He has a good cage and hidespots, etc. Oddly, though the temps are all good, he prefers to sit on top of his hot-hide (a little cave thing) and wait for people to walk by so he can strike at them. He could hide but for some reason chooses not to.

I really really hope he starts eating. I know he is pretty stressed now being in a new home, but he had a week or more to adjust.
If all else fails I will try convincing her to let me take him home and work with him (or not work, since I would basically put him in a less populated room.) It is really impossible to isolate him in the store (you know how pet stores are) and he is already in the "deadest" area of the store as it is.
Any advice would be great. We left a f/t mouse in his cage overnight last night, and he did not eat it.