So, others may have responded already - but I don't think removing the bottom 4' of wall is the best option. Given that the sheet metal proper walls block most of the breeze in the first place, taking down a couple of strategically placed sheets of the metal sides (for best cross breeze/air flow) and replacing them with good welded wire would be a much better overall help, I think.
My thoughts for best single sheets to remove: (won't let me draw on photo when downloaded, so have to describe here)the sheet/panel on the front left corner of coop proper, and back right corner of coop proper. That said, depending on prevailing breeze, might want to do one sheet center back and one sheet on the front of he shed that we can't see in photo, etc.
While it won't be a 2 second job, it shouldn't be too hard. Cut some 2x4s to length to fit upright between your horizontal runners, toe-nail them in so the form a 'solid' vertical line top to bottom the width of a panel, purchase some hardware cloth the height of the space between your newly created vertical 'runners. (I'm guessing your panels are 2" wide (26"), but some are 3'wide..... They make 2', 30" and 3' high fencing, so you should be able to find some that works. You can staple (or screw) the fencing into place under the remaining metal panels, The screws from them should go through the fencing - but you will probably need a few more to secure the fence well than what is used for just the panels.
This is something you can start working on before removing any) of the 'safe' metal panels! You can start cutting and placing the vertical 2x4 sections from the inside of the shed. (just be sure that your metal panels remaining overlap these 2x4s so they can be securely screwed back on all the way up). You should be able to order a roll of 1/2 in welded wire from Amazon. I don't know how tall your shed is - and shipping can sometimes be a bit high for something as heavy as fencing...but if you can even remove one panel that faces the prevailing wind for now, it will make a significant difference. So, 1 roll 10' long by whatever "height" you need to fit over the studs when removing a panel. (
example of fencing - TSC and Amazon also have a variety of selections.
(Note -if the panels don't run full length top to bottom (i.e. 2 overlap to run top to bottom), then removing the top 'half' of 2 opposite or kitty-cornered panels will be a big help, too!