Ideas to keep water from leaking into this tin shed?

[Baxter-Shamo]

So I've gotten myself a tin shed. Right now Im keeping tools, straw and my chicken feed in it, however I'm Hoping to make it into a hen house for my chickens sometime soon before the winter settles in so they have more room. I've gotten it up & cemented in but theres one problem, It has a flat roof and water leaks through! So I'm looking for a cheap and easy way making the roof somehow slope or another way of keeping the water out WITHOUT letting too much draft in. Heres a couple of pictures of my shed----




Any suggestions?
Thank you.

 

[enola]

Is there any ventilation in your shed, I couldn't tell from the pictures.
There is a product called FLEX-SEAL that sprays on to seal leaks. I haven't tried it yet, but am thinking about using to fix the roof where I have a leak in my chicken house.
Also, please remember that a tin shed will heat up like an oven in the summer time.

 

[Achickenwrangler#1]

Throw a tarp over it, then build a roof. Needs some windows for ventilation. Pics are really hard to see much.