interesting stuff - I am currently battling a problem at my house too. I had the bottom wood piece at the fireplace rot over the years and I failed to maintain. Now the rodents have taken up residence for the winter. Bill is right. This can take weeks to months since they don't always come out every day. One night I heard a bunch of noise in our fireplace flue. Long story short, one night I saw a possum coming out! Amazing how it fit into small places. I eventually trapped it in a cage and took it and released far away.
The Pro-Cone sounds interesting. I had the same idea. Glad one exists.
Here is the problem with rodent bait. PROS - it works great. CONS - the rodents eat it, and then can go back into your attic etc. Then they die. I had mice long ago that ate it in the garage and then crawled to the other end of the house and down into the walls and died. I had the worst stinch for months and months and months in my bathroom. It was horrible.
So, I don't know about that stuff.
I guess I would call the rodent professional if I were doing a Flip or had a rental?
I will be trying the Pro-Cone for now just to save money.
Either way - lesson learned. Prep your house for the Fall/Winter by covering up any small opening. You don't want your house to be a rodent Hotel for the winter.