Possum - Chicken Predators - How To Protect Your Chickens From Possums

I always find helpful answers in this page

We’ve had opossums, and we just rattle the door and they disappear. We put up a motion detector light, and we’ve not seen one since!

Helpful article about protecting poultry from possum attacks

threads for more discussions on key points. Great article!

I have a question: would the "ammonia soaked rag in tin can method" be an issues for the chickens, or would having the ammonia around the perimeter of the coop/run be far enough away not to irritate the chicken's respiratory system?