Puppy advice

[livwire68]

Here is the scene: about 7 months ago we adopted 2 large dogs from the aspca (Rot, husky, ridge back and other, well just big mutts) They were sisters and we had the ability to keep them together so we did. Great dogs, easygoing temperament and rarely bark. So I was at pets mart sat to get the girls x-mas gifts and wound up adopting a puppy. Mom is very similar looking to my girls. Puppy is a mutt, mom is golden ret. & rottie, I guess the father was golden ret. and pit. Mom was calm and quiet like my two girls. Well I have introduced the girls to their new baby brother, neither growled, but did a bit of sniffing. One really has no interest the other seems curious but kid of nibbled at the pup making it yelp, twice now. I keep them apart unless well supervised and holding the pup. Both dogs started drooling an extreme amount. Is the nipping and drooling normal. I continue to give a little more smelling freedom to the older dogs, I understand it takes patients, just not real sure how to read the big dogs. I know they will put the puppy in its place around the house and it may involve growling or nipping. Any further info would be of great help.