It's great that they have an option for only small dogs. When I was trying to find a place to kennel Cohen for the weekend, one of the places I called said they had this doggy day care set up, where the dogs were allowed to play together. I was intrigued until the lady told me it was all the dogs together. Just the thought of my baby running around with big doggies (especially since he thinks he's a big dog! lol) terrified me.
I'm sure that your baby is doing great. Like one of the previous posters said, it might be good for him. He can make doggy friends which will only increase the brighter side of life that you have given him.