Dogs are so much like people, and like people, two dogs play together well, but when there’s a third, there has to be a connection to make it work. Typically, when I watch three people out together, if it’s going well, one is making sure everyone is included in the conversations. I think something similar happens with dogs.
Two dogs will start playing then a third will join in; often this causes a challenge – do the dogs engage with the third? and if so, does the dog who is now left out, take it well? Even in large yards dogs typically play in small groups. A common strategy most dogs employ is to begin barking, escalating the excitement. This is often where stuff goes bad. But one of the best things that can happen is that the third dogs finds something to engage with.
In this picture, Lunchbox (darker Great Pyrenees) often plays with her brother Wells, but since he’s busy playing with Gordie, she grabbed a ball instead. This is the perfect scenario when you have more than 2 dogs playing or hanging together.