As above. Personally I wouldnt trust it as a long term deterring product when out of date. I would only use it after catching something with strike and would be keeping that animal to hand under observation.
I would use out of date crovect as the results could be monitored.
Its not ideal though.
In the future, ask the people your buying it off the expiration dates. Always a good tip, sometimes they stock rotate like any other shop. If you explain your small they will often have newer stock at the back. People who are going to use it in a year dont mind buying it for the year.