Out of pity, I adopted two young research mice who were facing euthanasia if they didn't find a good home. They're about a month and a half old. I've had them for roughly three weeks now and they are absolutely terrified of human hands. So far, I've been leaving my hand in the cage without trying to touch them and handling them on a table top. They refuse to run onto or touch my hand at all. They will, however, run onto my sleeve or arm. They will take their favorite foods from my hand and lick peanut butter from my finger, but they won't let me pet them or touch them. If I put them in my hand or scoop them up, they will run around it, but they won't let me make any more contact. They also can be bitey if I try to guide them onto my hand out of a tube. Is this to be expected? Is rough human handling just too engrained in them, or is there anything else that I can do to acclimate them to human touch?