Boneyard does not trigger

[Flamby]

Hello,

i'm new so i don't know if it's a bug or if there is a reason, but sometimes the boneyard doesn't trigger.

For example, i was playing against a top50 deck, i had 3 boneyards in play, i had 23 skeletons, and the opponent plays a rain of fire.
Suddenly i have 0 skeleton left, and no new skeleton is generated.
How is it possible? is there some hidden rule?

[Kamietsu]

Skeletons do not generate a new skeleton. Only every other creature does. So when your skeletons died, they were not supposed to generate new skeletons.

[jmizzle7]

Skeleton deaths don't trigger Boneyard. If they did, then the only way to kill a skeleton would be to get rid of the Boneyard first.

[Flamby]

oh....then i believe it should be written on the card, like "every time a non-skeleton creature dies" instead of "everytime a creature dies".
it makes quite a huge difference.
I guess it seems obvious for you because you already play the game for a long time and you know how the cards behave, but it is really not clear.