
A friend of mine who lived pretty isolated and didn't go to shows when she had pups got kennel cough at her house when she had pups that age.
The main problem was that they felt miserable and lost their appetites so were not eating and gaining as much as they would have.
They were given AB's prophylactically and cough medicine, and they soon caught up after shaking off the worst of it in a week or so.
They didn't go to their new homes until all signs were gone and they were fit and well, which in the event was only a week or so longer than usual, and their owners were happy to wait until the Vet had passed them fit to leave.
Remember to use probiotics for the pups to replace the gut flora killed by the AB's to avoid digestive upsets. A spoonful of Bio yogurt on each of their meals will be soothing too.