oh, also, good job on the crate training! It sounds like you guys are doing really well, and those potty pads are awesome!! Leave one or two in his kitchen area if you have to go somewhere, just so he has a place to potty if he needs to.

And, yes, PLEASE NEUTER HIM! you wouldn't want to have the same responsibility of finding homes for his own 13 babies, would you? Or having his own pups surrendered to the shelter? Neutering does improve agressive, dominant, territorial, alpha, wandering, barking behaviors 90% of the time, and it prevents diseases down the road than often occur in unaltered male dogs. You should also have the sister spayed, not only will it prevent her from getting pregnant and producing even more unwanted dogs in the world, it also prevents female cancers that affect many older unaltered females. Neutered/spayed dogs also typically interact with other dogs much much better, and they are much happier without those raging hormones...