This will happen when the pups are in a new environment where they arent use to. The best thing to do is to add (Some people hate this) human food like cheese or chicken/ham to their food. This will attract them to the food more than likely. Also leave the food out so they can go to it when they are starving. They will start eating again its just their way of coping with change.
How recently have you moved and how long has it been that they aren't eating?
Have you changed foods? If not, did they eat the old diet?
Do they have a new designated area for them to eat in? Are they on a new schedule?
I assume you feed kibble. Have you tried adding a little canned food, chicken and rice, etc to entice their appetites?