Definitely need to get them a toy that to focus that activity on, and play very happily with it. Then as the other poster suggested, tap the top of their nose when they bite things that are "off limits" and say "No." Then immediately re-direct attention to the toy they CAN bite, and play with it to make the association a positive one. Repeat consistently.
Belgian Tervuren's are smart dogs, if you are consistent, they will soon stop biting off limits things, and concentrate on the things that are allowed.
Make sure to play happily with them, and they will adjust their focus well.
Hope this helps!
Answered by TrueKnightTervurens - 3/5/2014 2:03:40 PM