MommaCat, I'm not an expert on luring cats. For expert advice, you can post under cat rescue where the cat rescuers will see your post.

I can tell you what worked for me, though. I started putting food out every morning near the igloo. Sometimes she came by, sometimes not. Then I put started putting turkey (Thanksgiving leftovers) in there every morning so she began a regular.

Then I put cat nip inside the igloo. I noticed the next day that the bedding towels were matted down and someone had slept in it.

Of course, canned cat food will also work and they can smell it from a very long ways away. It might also attract other animals, which is why I used cat nip.

I only knew for sure that it was her when I stepped outside at night and she ran out of the igloo. So, I guess I'm saying you'll need to check it personally to be sure it's the cat and not a possum.

Would your litter dome get more protection underneath the deck?

Did you put the mashed cardboard and papers inside a plastic bag before putting under the dome? Otherwise, they will get soaked and then freeze.

Should I partially cover the opening somehow?
I would to help keep the wind and snow out. Now that I know that the feral kitty is using the igloo, I have placed an old, large rubber-backed rug over the top that makes sort of a tunnel entrance to the igloo.

Good luck and let us know how it goes.

Pat

PS When I knew the feral cat was using the igloo for sure, I went to PETsMart and bought this warming device that you put in the Microwave and heat and then put in the outdoor house. It will retain heat for up to 12 hours. I just put it in last night for the first time. I found it in the dog section.