There have been some good flaxseed threads in the last couple of months that are worth searching and seeing all the ways people feed flax.
I buy feed grade, full fat flaxseed for all my farm critters and find feeding it whole does indeed make quite a difference. A huge difference in ruminants (multi-chambered stomach/chew cud animals.)
Where my horse came from, he was on mostly pasture with a little grain supplement and round bales of hay. He was ok healthy but had no real shine to his coat.
After getting him home, I started him on whole flax and even in his full winter coat he started to get some shine, but the change in softness is what really stands out.
As he has started to shed out I am noticing his color is much richer than it was last fall when I bought him. This occurs whenever I bring home any new animal, horse or otherwise, and start feeding flaxseed.
Because it is not very expensive for me, I will continue to just feed it whole. Anything that comes through undigested gets picked up by my chickens who work the compost.
Right now I'm giving about 2 tablespoons a day.