Guilfordbeekeepers.org

So, how many times can a hive swarm? We had two hives until late March when one of them swarmed. We captured it and had three hives. Then Easter Sunday the other original hive swarmed, we captured that, and now we have 4 hives.

Last week we saw another swarm (can't figure out which hive it came from) but it was too high up and it left. Now today, there's yet another swarm way up high in another Poplar.

Hubby just checked all four hives on Wednesday and didn't see any signs of swarming, but then, we don't exactly have a great track record of being able to predict a swarm!

After the first two swarms we added supers and we don't have queen excluders on.

Are we just really bad beekeepers or are we great swarm magnets? Could these two recent swarms be from the new hives or the old hives or from someone else (or even wild?)

Well...
It is not uncommon for a hive to cast off multiple swarms or after swarms.
I would sincerely doubt that the two you caught are from #3 or #4 unless they were well established and the brood chamber was over crowded.
I have had a nuc to cast a swarm, so it is certainly possible.
Typically about a week or two after the first swarm you might see another one. This is due to the fact that the swarm cells built were constructed up to a week apart. The bees are simply ensuring their survival. After the first swarm you might have prevented this by cutting out the remaining swarm cell, thus eliminating additional queens.
Swarms do not necessarily make you a bad beekeeper. If it was so then I would be one of the worst due to the amount of potential swarms I have dealt with. It has been an unusually swarmy year and you just have to do your best.
New queens and lots of brood room seem to help the most.
Are you noticing that you are quickly expanding your operation? Do the math and try and guess how many hives you might have by this time next year!

Kurt