What weight should my 4 year old hermann tortoise be, before

  Check out this link to the tortoise trust website on how to make sure your tortoise is a safe weight to hibernate:

http://www.tortoisetrust.org/articles/me ...



Hope this helps:)
this depends on his size as well. However you really should have him checked by a vet prior to allowing hibernation,. It is important to have alot checked