Are your puppies growling, barking, mouthing at eachother? I think this is very normal for a puppy to play like this. when we brought Bianca into our household this is how she would play with Dasia. She would get on top of her and growl and snarl, bark and latch on to Dasia's lower jaw. Mind you, Bianca is only about 15-17 pounds ( a wee pup) and Dasia is 50pounds. When watchign them play i thought they where goign to kill eachother. Dasia is NOT vocal in play but unfortunatly Bianca is
she sounds down right scary. However we NOW know the difference from playing and really fighting. Dasia has NEVER hurt Bianca in any way but a couple of times when Bianca wasn't listening to SIT and Dasia was Dasia got frustrated and slammed Bianca to the ground and snarled. We always check for marks on Bianca with all the "mouthing" they do, but NOT one scratch or nic on her! Dasia on the other hand....
poor pup she has scratches galore from Bianca's needle teeth. We always monitor their playing and we are trying to curb Bianca's growling and barking when in play.
After playing check both of them to see if any injuries like scratches and etc are visible. I'm sure that it looks like they are killing eachother but they are quite gently with one another.