On the YT server I am on, I saw a skeleton horse, spawned on top of the community post office (not horse hit by lightning as we have no horses near us on server) go near it skeletons spawned in on horses (which was fine).

Killed all of the skeletons, got 2 enchanted bow drops from it (probably luck) but one dropped a Power I, Unbreaking I and Power II bow... didn't think this should happen.

Also on server we have had about 5 of the skeleton horses spawning (which then spawn approximately 4 skeletons and 4 skeleton horses each time - wasn't too fun) don't know if these spawns should be rarer than we have been getting (this is in a plains biome.)

Thanks