Stall Flooring

We are currently re building our barn.  We have dirt floors in the stalls and are wanting to put a different flooring in to keep dust down and calves clean.  Some people have said to put rubber horse mats down?  What is the best way to do this?

Horse mats are a good choice, but need to be done right. 

If at all possible put a 4 inch lateral line in so that moisture can drain out of the barn.  Then you should put down some 2" clean rock that will also just cover the drain tile.  On top of this put some crusher run rock and pack it down to make a nice hard even surface.  Then you can put the horse mats down.

By doing it this way you can keep the urine ammonia smell down.

If it were me I would put the base down like CBC suggest, over the gravel I would put down a barrier mat, like you would in landscaping. Over that I would put 6 to 8 inches of ceder fiber and pack it, wet it down.

I like dirt with a little bit of sand mixed in with it, and covered by about a foot of cedar mulch. 

I agree.  Cedar Mulch is the way to go.  I've noticed a reduced number of bugs, ants and flies, as well as it keeps the smell down.  When my daughter and I pick up poop (it is a 50/50 deal but sometimes its 70/30) most of the cedar drops out.  Masonry sand is really good because it drains better than bank sand.