New puppy in home with established dog?

I have an Australian Cattle dog x border collie and a Belguim Shepherd cross border collie and my partner has just recieved a border collie puppy. I want advice from people who have had a puppy settled into a home with established dogs so i can make this as easy as possible. Today is only day one and i am being sure to fuss my current dogs and praising them when they sniff or show positive behaviour to the puppy - but at the moment - if the puppy tries to approach them and lick them or something - they growl warningly. The puppy backs off and if it doesn't they snap and it does so the dominance thing seems to be established but i want this to be as easy and encouraging as possible for all animals. I am feeding my dogs in smaller meals to coincide with the puppy and the puppy has her own bed. Both dogs are tending to avoid her. Please - any tips that help would be great.