Later that summer, during an especially hot and bright night (it's midnight sun where I come from because it's above the Arctic Circle) I saw that grouse on the tractor road further down the fields of the farm. It silhouetted in the midnight sun. It surprised me to see it standing in the middle of the road like that, like it was mocking me, so I got angry and chased it off the property.

It went off into the property of my grandmother's sister. And later that year, also she died.

But look, there's probably a reasonable explanation for it. When farmers grow old and sick, they often move away from their cabin, and in with their younger family and children further away, who take care of them. So when the house becomes derelict, wild and otherwise shy animals dare to move closer. But of course, old people would only move away from their farm if they were in a bad shape. And there's your omen and the logical explanation for it.

Does the Grouse know? Probably not. The grandmother would though.

It's known that animals can sense certain scents that can indeed be foreshadowing of death or health decline. Isn't it even the slightest bit possible that the grouse may have smelled something that humans couldn't begin to perceive? More importantly, do you have any proof or knowledge that would actively disprove this? No, that's not a requirement in science, but it is a handy discussion aid.