Hey did you know the ability compound eyes makes you 4 times more likely to find a Pokémon with an item. So you'd be 4 times more likely to find a destiny knot. It can have fainted and the ability will still work. It NEEDS to be at the head of your party tho. So when you go looking for an item like that you should get a Pokémon with compound eyes (butterfree for me), make it faint, leave it at the head of your party, then have a Pokémon with frisk in the second spot. That's how I found my thick club. Trust me it's much easier this way.