Isn't it easier to secure your run/coop than get into a war with squirrels?
In my years I have found the two to not be mutually exclusive... When I did home remodeling I repaired many a house/garage due to tree rat damage only to be called back a few months later to repair it again, and again and again... We are talking tree rats chewing right through brand new 3/4 wood siding and trim, or right through brand new vinyl siding... Once those rats discover there is a prize behind door number one many of them refuse to walk away without a fight...
The war against them is short for me, a Victor rate trap secured with a short length of chain has never failed me...