is it a slat mill, carpet mill, or a regular persons electric treadmill?
Yes you can start to introduce your pup to it so when he gets a bit older he won't be afraid of it... don't start running him on it yet though... IMHO i always allow my pups to get on it but not use it at that age, i wait till they are full grown before doing any real hard work like mills or jennies...
Play ball, walks, springpole and flirtpole together helps you build a great relationship with your pup and helps keep them fit... JMO.. good luck and have fun..