padding under trailer mats?

["marilyn wiese" <mwiese@gte.net>]

My trailer has rubber mats over a wooden floor.  For traveling to and from
rides, that are many hours from home, would it be helpful to the horse for
some cushioning to be under the rubber mats.  Would carpet under each mat
work?  I always clean the mats off after each use of the trailer and usually
will even take them out of the trailer and hose them off really well.  Is
there some other type of material that would be good to put under the mats
or is more cushioning not a good idea for any reason?

Thanks, Marilyn and Khal in San Angelo, TX (no rain at our place in more
than 2 months and it is VERY dusty)