We weren’t able to, we used corrugated plastic sheeting and they get in just fine ☹️, we remove the food at night and they stay away now. Took awhile for them to realize there was no more buffet though.
This is our run I’m speaking of, we have a hardware cloth “gate” we close off at night so...
Rats will show up, and rats will get in, I know because we have the same issue. I suggest closing it if you want to be rat proof. We gave up and just take the food in every night.
BTW your title says 34” gaps 🙂