This box simply needs an entry hole and a few finishing touches. You can often get the boxes for free from a seafood or steak restaurant or butcher shop, or recycle your own shipping containers. The box itself is made of insulation and is waterproof, and the material is very easy to cut using an ordinary kitchen knife.
Measure, mark, and cut a 5½” diameter hole in the box a few inches from the top and off to one side. Line with floor tiles to prevent scratching. Add straw. Glue the lid on, and add weights. This box is very lightweight, so added weight is absolutely necessary. To prevent water and snow from accumulating on the flat roof, set the shelter on a slight angle.