If I am not mistaken, Mann Lake carries/sells queen marking pens and cages. You may not know that each year is designated with a different color. That having been said, I quit marking queens several years ago as in my opinion it is a totally waste of time, especially if you have a lot of hives. You may have to spend a lot of time looking around the hive to find her even if she is marked. If that brings you joy then by all means go for it. The reality is that there is almost no need to ever look for her let alone find her. I concentrate on looking for "signs" of her. You can tell a lot if all you see is capped brood, or if you see capped brood along with larva, or if you see capped brood, larva and eggs. All of these have specific timings - for example if you see eggs you know she was there at least up to four days ago. In any event - good luck this upcoming season.