I've actually done predator control work here in wa for the game dept. Coyotes and believe it or not fences kill the bulk of our grouse.
I haven't seen it personally, but heard a very honest report that Ravens are tough on Sage Grouse chicks.
Fences can get a lot of them, but proper siting of them is an easy way to mitigate that. Ravens and magpies are hard on the birds as they are big nest predators. At least one relocation of sage grouse I'm aware of they used poison eggs to thin the ravens/magpies/foxes to help give the new birds a better chance of nesting success.
Look beyond the first couple of Google search results, then make up your mind for yourself.
That's internet gold advice...
