I've been feeding Purina Flock Raiser and never checked the date of manufacture, but when the most recent bag smelled kind of funky at the end, I realized I needed to learn how to check the date. At the store I saw various dates and didn't understand the code...so I called Purina. They told me that the first number represents the year. So 7 means 2017. Jun01 means June 1st. Since I learned on BYC forums that you want it less than 6 months old, and preferably less than 6 weeks, I chose this one, only 2 weeks old when I bought it. They had bags that were several months old. Maybe most of you already know this, but it was news to me. And to the employees at the store.