Hay stored outside before feeding suffers substantial losses of both yield and forage quality. Weathering losses in round hay bales are deceptively large. In fact, just a four‑inch layer on the surface can contain up to one‑third of the entire bale volume. A weather damaged 1,200 pound bale of hay would therefore actually provide only 800 pounds of feed.
Weathered hay is much less palatable to livestock than undamaged hay. If livestock don’t like it, they won’t eat as much. If they eat less, they are in a worse nutritional state.