We have two groups of dogs here every day. What we call the “small side” and the “big side”. (super creative names, I know). The small group is typically small and medium sized dogs (under 40 lbs) but there is some crossover. We have older or lower energy dogs who just do better on the “small side” but we make sure that any larger dogs on the small side are safe and play appropriately with the small dogs.  The big side consists of larger dogs (typically 40+ lbs) who are rougher and more energetic. This group is usually full of adolescent dogs who spend the bulk of their day being VERY active.