Fly masks protect horses' eyes and faces from fly irritation during summer, providing genuine welfare benefit when well-fitted and properly maintained, while poorly fitted masks can cause harm.
Summer fly control represents genuine preventive welfare management for horses. The constant irritation of flies around the face causes behavioral stress evidenced by head tossing, stamping, and self-rubbing. Flies transmit eye infections and deposit larvae causing habronemiasis. Well-fitted fly masks that are removed and inspected daily provide real welfare benefit. Poorly fitted masks that rub the eyes or face, are never removed for cleaning, or remain on 24 hours a day can cause their own welfare problems through pressure sores, skin disease, and eye irritation from ill-fitting material. Fly control is appropriate welfare management when done correctly.