Don't be silly, DartmoorLiz. It's a bespoke upcycled lamb warmer. Any similarity to a wooden box with an old caravan window slapped on top is purely coincidental!
The clever bit (IMHO) is that the plastic crate allows the air to come up underneath and around the lambs, rather than blowing down on top of them. There are
more details here if you're interested.
And thanks for the answer, Shep53; 37DegC it is

.