We have swath grazed it in mix with oats for quite a few years. You have to watch a bit, but I believe the awns soften up considerably in the swath. Also, the oats dilute the awns quite a bit. We still get the odd cow with a sticker in her mouth.
I swathed grazed some barley a few years back. It was dead ripe as we combined most of it but had a major break down that led to swath grazing. Has no issue's at all and they did a better job cleaning up than the Massey did!