Flies are not only a nuisance, but can transmit diseases to your horses. MultiFly Feed-Thru Fly Control is one of the most effective fly control solutions on the market, at the cost of only $0.36 per day per horse. This safe, pelleted formula provides 99.9% efficacy at breaking the fly life cycle in the manure of treated horses. Simply feed to your entire barn, and watch the fly population quickly shrink. | Formula 707 MultiFly Feed-Thru Fly Control for Horses Pellets | Size 5 lb