Hi Howard,
Funny you should ask. So I trapped one a night for four nights in a row. On my trail camera, the activity dropped way off. With the smaller sized hardware cloth along the side they were getting in, they were now blocked off. I was getting what appeared to be a single rat - though one can never tell, they seem to all look the same- that would come by and check things out, but give up after 20 minutes of running around. No holes anymore in the morning, etc.
So, things look great.
Yesterday morning, I fill my hanging feeder up. This morning, I go out and do my daily check, and I notice that my feed has gone down a lot - like probably more than what 8 birds could get through in a full day and morning of feeding. But, I can't find any holes or any tunnels. So, I start really looking around and notice that I have one gap high up on my roof line of the run. It doesn't seem likely that they were going in there, but I block it off anyway. So if that was being used, it's blocked off now. I then start looking over my gates that I use to go in and out of the run. The gaps aren't very big, but might be a bit over the 1/2" guideline. So, I grab some left over lumber that I had from the run, and I start framing in on the inside of the run where the gates close. If you're standing outside the run, the gates swing out towards you. So, I can frame the inside of the run, and make it nice and tight for the gates to close up against. I decided to do just that, and now my gate area is fully secure. I'm really happy with how it turned out, and there is no way to fit through any of the cracks around the gates with the gates closing up against solid framing lumber.
Tonight, I think I'm going to point my game camera on the inside of the run and see if I have any activity. To my knowledge, there are no more reasonable locations that they could get in. I say that understanding that I could be wrong, but I'm hopeful.
I checked the bait stations, and I don't think they've even touched the bait that came free with the stations. The recommended professional stuff arrived the other day, and I'll probably break that out in a day or two. I'm thinking that the bait hasn't been touched because they were still getting access to the run.
We'll see what I find in the morning on the camera.