Sounds like a plan.
Then they crawl under your house and die.
In a couple of days you will realize that you made a very smelly mistake.
I use .22 shorts.
They dont make much much noise and are very effective.
a .177 pellet out a Crosman 760 makes little noise too!
"I use .22 shorts..."
Shooting a feral cat is much more humane than putting antifreeze out for them to drink. I can't believe someone would even suggest that.