We brought Rover home yesterday and introduced him to Max and Sadie. It went well.
It probably helps that Rover is younger and smaller. Max is almost eleven and Sadie is eight. Rover is around two and they seem to view him as a puppy. They were not aggressive with him. However, Max, the ball bully, established that he is the king of the fetchers.
Sadie and I took Rover for a walk around the barnyard, the arena, and the river, trying to show those as boundaries. So far, so good. Our place is not fenced, except by barbed wire, which, of course, does not contain dogs. I actually think it will help for him to have the example of these mature dogs. Since they do not roam, let us hope that Rover gets the idea that roving is not acceptable.
He has lots of energy. It is also a compatibility match that Rover is a sporting dog type. Max and Sadie showed him where to swim within the first five minutes of meeting. He has now jumped into the water countless times, gotten out, run around like crazy, and gone back in. Apparently, he is a water dog too.
Welcome to the family, Rover! You just might fit in.