I add the Animal Omega horse supplement into my horse’s grain
Like just about everything: little as possible, as much as necessary. Look at what each part of feed does and determine what's needed based on that. A high protein diet isn't much use for a happy hacker, extra iron supplements are not much good if the horse doesn't need iron. If the horse is healthy and energetic without feed, I wouldn't give them anything extra. It takes some changing to determine the right mix/amount. Just be sure to change slowly and gradually.
As for hay/haylage: if the horse is prone to coughing, then haylage or damp hay would be best. If the horse is a do-gooder or prone to scour, then hay would be better. Ad lib if possible, little and often if not.
For base feed one eats marstall haferfrei cause he gets crazy off too much oats, as extra after a ride: marstall mash (as a base and some energy), force( for minerals,electrolytes and vitamins), msm(for joints) and farriers formlua (for his poor feet).
The other one eats racing selected (for sensitive stomachs, no oats) and as extra: racing speedpower(for energy, again no oats), chia seeds(for coat and hoof wellness, general superfood) and msm+ginger(for joints).
I determine what they eat based on in what kind of use they are, is there something they can’t eat (with my horses we stay away from too much oats as it gives them dumb energy, some horses are prone to ex. ulsers) and how they are to ride.
I feed Seminole Wellness and love it!!!