Puppy old enough to run?

Question
I have a Greman Shepherd who is almost 4 months old, and I was wondering when he will be old enough to run?

Answer
You can let him run and play in a fenced yard, but wait until after he is a year old to take him jogging or anything.  His joints aren't ready for that.

To give them more time to develop under less stress, switch to an adult chow now.  It delays reaching full size.