Sheep Shelter built for $0

[mysunwolf]

Maybe you could use old roofing (or concrete board, scrap plyboard, etc) as siding all along the bottom half to provide more protection? Then wind could still blow through the top half, so the structure wouldn't be as likely to flip, but the sheep can lie down and be completely out of the wind.

 

[Baymule]

You could find some pins to drive in the ground to anchor it. Pins like rebar bent with a hook in it comes to mind, or T-posts driven in the ground and secured to the shelter. You could find more pallets, take them apart and use the slats to nail to the shelter walls to deflect wind. You are on the right track, keep up the good (cheap) work!