@Gracie01: What did you use to keep them out?

I used hardware cloth, or something similar, with small holes. I cut it twice as high as the opening, then bent it in half and stapled it on. The bent half laying on the ground was then buried under the dirt. Does this make sense?

I agree with Gracie. Quarter inch hardware cloth (wire. I don't know why it's called "cloth.") Make sure it is buried at least a foot underground and then bent outwards from the deck so they can't dig under it.

Thanks Gracie & Susan. I will follow your advice.

I used 1/4” hardware cloth. So far no problems.