When I was a child we had a sweet cat who didn't purr. He was separated from his mother too early and never learned. Some years later we adopted a stray female who purred all the time and he learned how to from her. He also was frightened of mice... his mum never got to teach him much of anything! I hate to separate kittens from their mothers too early because there's so much they need to learn to give them a good start on life. What's a few weeks more?