Yes, legally speaking, “natural” on a meat label only refers to how the meat is processed, not to how the animal was raised. However, some meat companies — starting with Mel Coleman decades ago — have used “natural” to signal that no antibiotics or hormones were administered to the animal during its lifetime (though some companies allow antibiotics up until a specific withdrawal period before slaughter).
This has caused confusion in the marketplace, as consumers wonder whether meat labeled “natural” means no hormones/antibiotics or just the legal minimum of no additives/preservatives during processing.
To reduce this confusion, the Agricultural Marketing Service of the USDA has created a new term, “naturally raised,” to refer to meat from animals never treated with hormones or antibiotics (except some parasite-reducing ionophores). It doesn’t tell you whether the animals were confined or raised on pasture. You can find the full definition here: http://www.thefederalregister.com/d.p/2009-01-21-E9-1007.