You might consider french drains inside with an elevated floor. French drains would direct any liquid outside. Dig the floor up and install the french drain pipes, cover with pea gravel, then cover with sand/dirt, then maybe decomposed granite to hard pack the barn floor?
The inside of a barn will always wear away since every time you clean up the manure and pee you are scraping up some of the floor. You may just have to reconcile yourself to infillng the barn floor every year in the spring after cleaning out all the winter debris.
I'd try something like "crusher run" which is a fine "grit" like little gravel... it packs well and will allow some of the wet to filter on down through but not much. and it you scrape some up and it goes into the compost or garden, is not like rocks or anything... aerates the soil a bit....
I got to put hands on Oreo's ear. There is a neat small hole thru, no rip! So I guess the extra blood on underside of ear was from tag edge scoring not ripping. SO HAPPY!!!
Today we got the rotten bottom board along north wall pulled out and replaced on half. We also added a new board at sheep rub height and re-secured the tin. The lower board is a 2"x6" and we will raise floor a couple inches.
On outside of north wall, we removed some stumps and prepped edge trim for lean-to roof. I also cut down dead tree for convenient corner post and edge board to length. This lean-to will store my tools and feed drums.
Major framing for the lean-to is complete. Still need to final trim uprights and add cross rails for tin. The front lip is a 2"×4" and I can step in at corner without hitting my head.