I found whilst fighting and killing a skeleton, that it dropped a bow, much less drop % then a bone or an arrow, but still. Stranger yet, I found that a zombie dropped an iron helmet, at an even lower drop percent, as I only found one in my stay here in this well-matured, friendly and helpful community/server. If I find more, ill be sure to update this!
Its part of the new update. Zombies have iron helms, legs, shovels, swords. Skels have bows and enchanted bows.