On our 2012, I found (shortly after purchase) I could "see light" from inside the MH with the slideout closed looking down at the back edge of the slideout (just in front of the bathroom sink). I contacted the dealer, who referred me to FR, who said "no seal at the bottom exterior of the slideout is normal". Gave up and bought some foam stick-on seal (1/2 inch thick by 1 inch wide, as I remember) and stuck along the lower edge of the MH body where the slideout would contact it when closed. Seemed to do the job for us.
I've also read on the forum here of others finding openings where wires and plumbing enter the MH from below. FR seemed to do quite a job on ours with some type of spray foam on these holes.
Finally, when in the storage yard, I spray around the MH with ammonia. Others have reported using mothballs in and around the vehicle, and other "rodent discouraging" approaches.
2012 Solera "S"
Calif SF Bay Area