Last April 2010, We purchased and used a small bottle of injectable penicillin from the Cenex to treat a chicken (with a compound leg fracture, amazingly, she healed) The pull date on the bottle is September 2011. We kept it cold in the fridge, but it settled out into clear liquid on the top and solid white on the bottom. I am shaking it back up and it seems to be mixing back together. Anybody know if this is still good to use today, on our duck with a foot infection (NOT bumblefoot, probably a sprain and dislocation that has popped back into place). Thanks!!