A good place to start would be Kentucky Equine Research. Kentucky Equine Research
You can ask them to help you formulate a diet for your horse. As a guide, below are 3 different horses and their diets. All are fed hay morning and night. Angel is stabled at night, Joe and GK are paddocked 24/7.
My friend feeds her 7yr old Pre-Novice (EvA105) TB Eventer
2 1/2 plastic feed scoops of Pegasus Liberty
1 x 5L bucket of Lucerne chaff
1 cup of Omega Feeds Weight Gain.
This is Joe- Joe1.jpg Joe3.jpg
What Joe gets fed is pretty much the same as my bosses 2* & 3* horses.
I feed my 15yr old Intro 1 (EvA80) Andalusian x TB/Riding Pony Eventer
1 x 5L bucket Lucerne chaff
1 x 5L bucket Oaten chaff
1 cup black sunflower seeds
1 1/2 cups flaky bran
1 teaspoon kelp
1 teaspoon dolomite
1 teaspoon brewers yeast
60ml Apple Cider Vinegar
And 3 times a week he gets a 2 cups of Millet and 1 cup of Linseed (Flaxseed) boiled up.
This is GK - GKharv.jpg GKgidge.jpg
Another friends 7yr old Welsh x Pinto eventer mare gets
1/2 a 5L bucket of Oaten chaff
1 plastic feed scoop of speedi beet (after it has been soaked)
1 teaspoon of garlic
1/4 of a cup of Equijewel
Angel - Angelcakes.jpg Angelcakes1.jpg
All of them are in good condition, all of them are fed completely differently.
It depends on the horse, their workload, their breed and their temperament.