do you sell feral cat houses that protect an outdoor cat from the cold, that you do not have to put together?

If not, place a smaller plastic tote w/lid inside a larger one, stuff insulation between the two and on the lid off smaller tote before putting on the big lid. Cut hole for cat entry. You'll have exposed insulation at the cut that you can pretty up somehow and prevent it from getting wet/destroyed etc. Just a rough idea.... Make it your own :)

I think they have the plastic igloo style.

They might i dont work there and if they dont they will tell u who does