Advice on Ventilation, pics included

[aart]

Looks like the whole barn is underventilated....might not have been built to house livestock.

 

[sunnie7]

Looks like the whole barn is underventilated....might not have been built to house livestock.

Advice on what to do to fix it at this point? Without having issues of rain coming in.

 

[3KillerBs]

Advice on what to do to fix it at this point? Without having issues of rain coming in.

Top-hinged windows and/or awnings are one option.

You can see top-hinged windows on this coop: https://countryliving.blog/2021/06/15/my-coop/

Extending the roof to make overhangs to shelter soffit vents is another. Here are two articles:

https://strousehomeinspections.com/blog/structural-roof-extensions.html
https://www.backyardchickens.com/ar...e-overhangs-eaves-of-a-shed-coop-house.76599/

 

[aart]

Advice on what to do to fix it at this point? Without having issues of rain coming in.

It would take some major construction modifications.
3killerbees has laid a out a couple.
You mentioned roof turbines, that might work if they were powered with barn safe fans.