Very cool! Feral hives are neat. I currently have 6 hives - one is dying (they killed all the queens I've tried to keep in the hive). It's a really fun hobby. Just like gardening, you constantly learn. This is my 8th year.
If you have other beeks in the area - or a local club - it would be great to find a mentor. Talking through things - the many, many iterations of things that can go right, wrong, or in the middle - is extremely helpful. As well as having hands-on guidance from an experienced beek.
The "killing the queen" thing can just happen. And it created what's known as a laying worker. Without the queen's hormone for acceptance among the colony or suppression of the workers' urge to lay eggs (workers have undeveloped ovaries, but can lay eggs in these kinds of situations), that hive is a drone factory - none of the eggs are fertilized, so they're all boys. Probably TMI right now!
Good luck!