4 month old pup

Question
I have an EBD male of 4 months and he and my female EBC of 7 love to play (or I think it is playing).  The Pup chews on the older dog and pounces on her.she barks/ snaps at him but never hurts him. they wrestle and i Think it is safe though I am not sure if I should leave them alone together.. The older one hates all other dogs but puts up with this puppy (curious if it is a breed thing)? Also Question 2 I how long should you crate train a puppy?  and should you move on to paper training at some point.  I am feeling guilty leaving him for 4 hours at a time in a crate..  Thanks, Amanda

Answer
I wouldn't trust them alone together. She could change her mind about him and he'd be in real trouble.

You should crate train forever. The length of time the puppy is out of the crate gets longer as he gets older and is more dependable in the house, but the crate is part of his life. Four hours isn't terrible, but it's the max I would leave a puppy crated at a stretch.