So sorry for your loss. If you wish to find a cause of death, your state vet could perform a necropsy. The body would need to be refrigerated and shipped or taken there. Here is a link for that information: http://www.usaha.org/Portals/6/StateAnimalHealthOfficials.pdf
Chickens recover from wounds where bones are showing, from injuries and attacks. But not really knowing the cause, you can just use first aid treatment and try to get it healed. The skin will eventually cover the bone as it heals. Has the chicken always walked normally?
I was just reading your thread about her bumblefoot 2 months ago. Is this the same leg as the bumblefoot? I would wonder if this is related, especially since it wasn't the typical bumblefoot with a scab. Has she ever had any respiratory symptoms or has she layed down a lot instead of roosting...