DLCs in Giveaways

Of course.

Thanks! :D

If it's on the list (you're able to select the game/DLC), you're allowed to give it.
The exception being a game/DLC that went free just recently and the mods haven't had time to update the list - in that case it'd be against the rules if you deliberately give it away though you obtained it as part of a mass drop of free keys. Usually free games are removed from the list within a few days.

Just make sure the winner doesn't have the DLC for sure before sending, because sometimes we are allowed to enter gibs for DLCs we already own