Originally posted by Nerevar:

the only enemies that are truely hard to lose are wolves and anything that can fly (aside gjall and seekers) the rest is easy to lose.

and most flyers have basically no hp to speak off. wraith excluded but that thing is a night only spawn. wiki claims they can spawn in crypts but i have NEVER seen one in there in all the crypts i plundered so probaly wrong or outdated info.

I have seen a wraith inside a crypt bot only once and pre-mistlands. The chests inside the crypts can contain chains. You might find enough that you don't have to hunt wraiths for chains.