What are the major welfare issues for wild animals (as opposed to conservation issues)?

Here are some examples:

• Wild animals in captivity – what do they need for a satisfying life that is comfortable, healthy, socially appropriate (e.g. not crowding habitually solitary animals together or  confining gregarious creatures in solitary enclosures) and not consistently boring.
• How far to interfere with natural processes – generally it is best ecologically  to let predator/prey interactions etc. take their course in wilderness areas, but I have heard of cases where a diseased or injured wild animal was left to suffer greatly for several days rather than interfere with nature and dispatch it, and a shorter period of suffering for an animal that was obviously doomed would not have been a conservation issue.
• Injured and orphaned wildlife – they may not always be a conservation problem (i.e. many very common species  get bitten by dogs or hit by cars) but as a suffering animal  they need the same kind of attention as a rare species or an injured domestic pet.  What to do with them afterwards can be problematical if there is nowhere obvious to release them (e.g. their homelands have now been cleared of forest and there is no other patch of forest which is not already occupied by others that will defend their territory).
• Viewing of animals in the wild – how much stress might different species feel in different situations, and how can we minimize actual dangers (such as birds deserting their nestlings in the presence of predators or icy winds, or predators being stopped from hunting)?

Any comments?