[Mastray]

We never took ours hiking at altitude, but I think you would want to be VERY cautious and maybe start off with some short hikes to see how it goes..With those broad chests & short noses, breathing could be difficult and it wouldn't be good if you got up high and Gus was in distress...I think like any other form of exercise that we do, start slow and work your way up and see how it goes..Plenty of hydration and good breaks as well

I'm gonna go with that!