The end of a short tale that can be found here: [link] ; one of the lesser known of Ye Olde Faireie Tales(e!)
Now most tales that seem massively violent and depressing have their own morals that have been obscured over time (The hare's Bride for example is about not eloping or things will turn to poop.) But this? Seriously this just seems to be a jolly tale about how once there was a rooster and a hen, then everyone died The End.
I mean DUDE, if you want to traumatize children, at least make an ATTEMPT at an excuse!
Nobody ever said folk tales were supposed to be light-hearted and have happy endings. Quite the opposite, in fact, as they normally were morality tales. As far as I know these guys didn't actually make these up but rather collect them and write them down.