Consider making one of these. Maybe squirrels would not feel secure putting head into opening.
Just like mentioned in above post. I never have issues with squirrels eating chicken pellet's. I feed my squirrel pets BOSS
Hunger is a terrible thing to convince against.
I also feed my wild birds their own seeds.
I know that many peeps are in a Panic mode with the Avian Flu. It is not going to affect every last chicken on earth.
The large chicken farms that do sometimes encounter the flu,,,,,, their chickens do not ever see outdoors.
Having chickens for over 20+ years now. Have encountered some losses, but not to the flu.

Do your best,, and enjoy your flock.
WISHING YOU BEST,,,,,,,,,,,,