No, I didn't think it was possible either. I've worked selling PML products, horse wormer, sheep and cattle wormer etc and they're very strict at recording batch numbers and expiry dates. Just thought this was odd but I will try Googling the batch number and see if anything comes up.
Just wondering, is it possible to have Vaccinations with the same batch number but with expiry dates over a year apart? Very confused at my horse's vaccination record on his passport. The first vaccine has an expiry date of April 2016 (administered in April 2016) and the second one done a month...