I give a lot of fatty acids in my diets. I simplify mine by giving either dac Oil
. Flax seed and fish oil are excellent sources of Omega 3 Fatty Acids that are well utilized by the body.
I had an allergic to everything mare that did well on 1 oz of dac Oil and 2 oz of Bloom twice daily. I gave her that much due to how bad she was. Most horses will do well on one or the other, but again they can be given together.
All of my horses are either on Dac Oil or Bloom plus what they individually benefit from.
Too much washing with shampoo will also strip them of natural oils and dry out there skin. Good old fashioned brushing may be all you need - but look at your diet and see how much fat is included.....plant source fats are a bit different from us getting saturated fats from meat. I look for flax seed and stabilized rice bran in my feeds.
Also double check that that is skin flakes and not lice!!