Tiny Licorice was like that when we got him, I trapped 4 of them and one managed to excape the trap but out of the 3 I did get, Lic was rotten. Once he could he ran at the kennel door and just kept doing that when I was there trying to change litter, water, food. Then one day I wasn't quick enough and he latched on and ripped and tore and death rolled my arm and hand. OUCH, OUCH, OUCH, it still hurts just thinking about it.
When I brought the kennal in the house from the mudd room, the three were still scared but 2 were better at being held and petted, returning love. Not Slickity-Lic though, he was still mean. Finally, the other 2 were placed in loving homes and Lic, being so violent stayed, we opened the kennel door but he'd only come out to hiss or swat at us or the other kittys.
Altogether I think it took him like 6 weeks to come out and be comfortable, now he's a tiny little love bug, exspecially in bed, he
to go under covers. He purrs so loud it vibrates the bed. I'm glad to have kept him.