I think I answered this for you through Yahoo, but I'll reiterate it here so other folks having the same issue can read it.
I would hold off on rushing out to get a new cagemate. Give your chin time to grieve a bit. Offer her a chin safe stuffed animal for now to cuddle with. Sometimes that's all they need to get through the grieving process. Your first little girl died in a pretty traumatic way and it's possible that the surviving chin was party to that, even if she wasn't injured by the cat herself. That could be part of why she's so upset. I would offer her a stuffed animal to cuddle with for now and monitor her closely. Make sure she's eating, drinking, peeing, pooping, normal activity - all the stuff that would be normal for her. If all those things are fine, and she settles down with the stuffed friend, then you might consider getting her a new friend.
I will say again, as I said in my email, that I would look for a cage with 1/2 x 1 inch wire openings. That will absolutely prevent your cat from reaching in and grabbing your remaining chin. With him already having done this once, the odds of him not trying again are pretty slim. The wire you wrapped the cage in is a good temporary idea, but I would want something more secure and permanent.
Again, I'm sorry about the loss of your little one.