Armitage's Chicken Foods

This was bought at auction as part of a lot. I was told it was British war time feed bag and was the only chicken feed company recommended by the Queen (I'm not too sure if that's accurate or if I have stated it correctly). It came already framed but I estimate the actual piece is 12" tall and 20" wide. I tried looking it up online and found some general references but nothing quite the same. I'm curious about the history and if there are any auction comps I can reference. I'd appreciate anything you can provide!