I feed Omega Horseshine, which is a stabilized ground flax, Several dealers now carry it around here, but I still order it online; the cost is STILL less that way, when you consider retail markup, sales tax locally, and the cost of me going to get it at a dealer's!
It is certainly NOT 'powdery' nor dusty; remember, flax is 'oily'.For 5 minis, It takes me @ 6-7 mo. to use up a 50# bag; Omega's is guaranteed to stay stable/usable for up to a year, PROPERLY STORED...I keep mine in my feed bin(an old telephone booth, laid on its back and w/ a plywood 'lid') in my insulated barn, which is well-ventilated and free of 'extremes' of temperature, out of the sun,and protected from moisture. I definitely see excellent benefits in coat quality and shine, and hoof quality and growth, in my horses!
Margo