Some birds have incredible metabolic rates --> take for example a humming bird.

However if I were to assume a canary has twice the human metabolic rate, it isn't a very good sensor. So, the canary dies half as soon? But the canary isn't even about poisonous gas. I believe it's about explosive methane gas, as their gas lanterns would need to be extinguished if the canary died, or else the gas leak that killed the canary could explode.

So, yeah, anyway. I think your information on this example is wrong, please feel free to correct me

We then had a thought... what if the mice were also eating the dog food in the garage? The container lid for the dog food was not very strong (weak and flexible enough that a mouse could possibly squeeze in and out), and coincidentally, that dog food was also high in Vitamin K.

Once we got better sealed containers to store the dog food, it only took a few days before we started seeing delirious, sick mice running around aimlessly in plain day light. Shortly after that, we stopped seeing them entirely.

It's possible the dog food was not reversing the poison. Maybe with the dog food locked up they started eating more bait, or maybe it simply took longer than we expected for the poison kick in. But regardless, we definitely learned a valuable lesson about keeping the pet food well sealed!