Cold-pressed linseed (flaxseed) oil is the standard plant-based omega-3 for horses - fed for coat bloom, skin condition and as a source of slow-release energy that does not add starch to the ration. Cold pressing matters here because heat damages the fatty acids the oil is bought for.
Available in 1L, 5L and 20L.
Linseed oil oxidises faster than most feed oils, and a rancid oil is worse than no oil. Buy the pack size you will use within a couple of months of opening, keep it sealed and out of the light, and smell it before each feed. Introduce oil to a feed over a week or two - a full dose straight up will loosen manure.
Feeding
Rates depend on bodyweight, workload and what else is in the ration - follow the rate on the pack and build up gradually. The 20L drum suits multi-horse properties; for one or two horses the 1L or 5L will stay fresher.
Not to be confused with boiled linseed oil sold in hardware stores for timber - that product contains metallic driers and is not feed grade.
See the full Gen Pack range - single-ingredient stable and paddock supplies packed in Australia by Eastern Distributors.