LHCb provides unique opportunities to study W and Z boson production at forward rapidities at the LHC. It has recently been suggested that a measurement of the W boson mass by LHCb would complement measurements by ATLAS and CMS. All measurements of the W mass at hadron colliders are subject to PDF uncertainties, but there would be a partial cancellation of the overall PDF uncertainty when the LHCb result is included in an average with measurements by ATLAS and CMS. Here we review measurements of W and Z boson production by LHCb, and report on a new study of the PDF uncertainty on the LHCb measurement of the W mass. The latter study includes the proposal of a new approach that should reduce the PDF uncertainty by roughly a factor of two with LHCb Run 2 data.