The immediate cause of the USDA's shift on animal welfare was a proposed rule, more than seven years in gestation, that would have required "organic" egg farms to give hens at least a square foot of space inside as well as access to the outdoors. The rule would have prohibited the large scale "organic" egg farms that The Post wrote about in July, in which the birds were kept in barns containing 180,000, at a density of three per square foot of floor space, and never allowed to set foot outside.