All my buns are in outside wire cages with no " igloos" to hang out in, I live in the south where it's hot almost year round. The only time I have put huts in for them was during a really cold and wet December a few yrs back thinking they needed more protection from the weather, they did not use them except to hang out on top of them and chew the corners. They also dragged them around the cages, turned them on the side and used them as potty houses so them came back out pretty fast.
My rabbitry is outside. The cages are in a three sided bunny barn. The rabbits need protection from the weather and depending on where you are, lots of shade in the summer. Good ventilation is a must, and remember it gets hot when you are wearing a fur coat!
Just because rabbits, in the wild, burrow doesn't mean your rabbit needs to burrow. Mine are quite content without anything in their cages in which to hide. Even when I give them an empty oatmeal box to play with they do not hide in the oatmeal box. They may stick their heads in and have to shake it off, but they don't hang out in it.
Don't mean to laugh, but my cages need a bit of work. Long story short, I have about 5-6 American Blues free ranging in my barnyard right now. I have put pellets and water in the hay barn for them, and they are very happy. I will try to catch them and process them, then fix up my cages by spring. It's getting cold out, but they are doing great.
Well, I have natural housing and man made housing for rabbits.
Have an enclosure where females go to rest or fatten up and there is a firewood pile where the dug themselves some nice caves and do great in there.
But then when it is time for some of them to deliver bunnies them move into man made apartments.
I have seen some nice outfits with man made caves for rabbits made out of concrete blocks and dirt on top.