Maybe to house a broody chicken. One of mine was broody for weeks despite the fact that I took her out twice a day and closed the run in the afternoons and weekends so that she couldn't get to the nesting box. Then I read here on BYC to put her in a coop with a wire bottom part. I happened to have one that I don't use, so my DH put it in the run and I closed her in there with food and water and she cold still see her friends. The next day she was cured from her broodiness. So, long story short, I think it will work well for that purpose.