Tonight we said goodbye to Dillon. Dillon was a 1yo Border Collie mix we took from a rescue just before Christmas. While he was very sweet, had good leash manners, and got along great with Mack, we were having problems. Dillon was getting aggressive with the horses, and had starting jumping at the faces of the ponies. Additionally, he was consistently running away whenever off leash. So, we talked to the rescue, and the wished for us to rehome him locally. After 2 weeks and a number of inappropriate candidates, we finally found what we hope will be a good home for Dillon. Mack might be a little depressed, but I think he will appreciate more focused attention from the family (the kids like him better).
That breed is a very busy dog. Loves to work and part of his mannerisms is showing aggression to the horses and the like. I know of one dog that when he got bored he would “heard”the kitchen chairs. Piling them into a heap. Best wishes in finding a good pet and pal for Mack.
If Mack is lonely, I’m sure I could “loan” you a beagle mix. He likes to wander (just as Dillon did), but I’m pretty sure he is too short to go for the horses. Anyway, good luck if you decide to find another dog.