2nd Shift: They use a bottled on date. It's a hand sticker on the bottom of the bottle, format MM/YYYY.
3 Dachshunds: They use a bottling date which is on the cases only.
21st Amendment: They use a packaging date. The packaging date is on the bottom of each can and on the side of each six pack. It is a Julian date that will read, for example, 13121. that is the 121st day of 2013 or May 1.
603 Brewing: They use a bottled on date which is handwritten on the bottle.