Oats are higher in fiber than most other grains, however, pound for pound
they have a much lower energy content. 
  
Whole oats can be fed, but many will pass through the stomach and intestines without being digested.  The older and younger horse, horses with teeth problems, tend to have more difficulty chewing and digesting oats.  Different processing techniques are used to make the oat easier for the horse to chew and digest. 

Crimped oats are lightly crushed to crack, but not remove the hull. Oats can be rolled flat, like oat meal. Whole oats can be clipped, a process in which the pointed ends are removed. Cleaned oats are sieved to remove foreign debris such as chaff, weed seeds and weeds.

It pays to shop for good heavy oats, (sometimes called racehorse oats)  they contain
less foreign material and weigh more per volume.  The individual grain should look plump, light blonde in color and fairly uniform in size.

Roasted To Perfection uses heavy, roasted, crimped oats for optimal digestion
and absorption of nutrients.   Cleaned oats are used due to fire hazards when roasting.