I saw a re-creation of a Sheiling in Scotland. and it was like a cairn set into the bank, or an igloo set in a hollow in a bank. "One man tent" would be the best way to describe it, though in stone.
low entrance (probably covered with cloth). Shepherds shelter and shelter was about as far as it got.
We knew a shepherdess in the Malvern area and she did not turn up to the session many nights because at lambing time she was out all night watching the sheep - foxes would go for the newborns.

I assume she had a LandRover or tent to shelter in.