If I may give some dog trainer advice, you are going to spend water and energy making some squirrels just a bit more challenged to the feat, consider just attra

If I may give some dog trainer advice, you are going to spend water and energy making some squirrels just a bit more challenged to the feat, consider just attracting the offending ones to elsewhere where they find some cheap/disposable food source so they let the chicken's alone :-) — this approach is usually cheaper and renders more results with dogs, cats and even chickens themselves! Say, once you detect them, you lure them to a certain path or place, maybe with some LEDs or scent or something you can automate dispensing (I don't known squirrels).