It's not just the temp either.
Some chins just go nutz, and after a life in a cage they can over do it.
The only time I ever had a chin keep it up like that, and even in my arms, was because of over exertion.
I've seen several case now, and in Newfoundland it's not the heat.
Big fat chins who get too long out of the cage can over do it.
If a chin is getting to many treats, sweets, in trying to burn it off they over do it.
You know yourself if your sitting at a hockey rink it's freezing, but play and your over heated.
Give a child candy and watch them climb the walls, chins are the same.
They can over heat in the cool if they are over doing it.
Don't give them as long a run, and give them a little shot of maple syrup or something after to get their sugars back up.
Dakota got so bad he had seizures, and went into shock. He went off his feed for a few days, and had 2 trims after.
That was months ago, and he's been fine.
I just don't let him run as long, nor chase a female in heat. He just couldn't take it being 950-1000 grams.