I know the sort of flooring you mean, and it's perfectly legal. I had one like that on the moorland farm. It can be slippy when wet, but isn't when dry, so it's important to use enough sawdust to keep it dry even when the sheep have emptied their capacious bladders all over it
One thing you must check, though, is that any fixed flooring is still sound under the outer surface. Repeated washings out can seep around the edges, soften the underlying wood - and one day the floor just gives way :0
We've only ever been questioned over ramp angles and side rails.