Your hidden field isn't included in your </form>. It has to be inside the <form></form> tags. And you should have a different value on each page. The point is to identify which page they are using, so a hidden field with different values is probably the best way to do that. If they have the same value you still can't see which page is being used.
Can I also see the email body page. I'd like to look at that as well. How many spam messages are you getting daily?