sudden, unexplained weight lost in birds is usually a sign of Avian Tuberculosis. It is carried by mice. When they get into the feed, their urine and droppings get on the feed. Any bird that eats this feed will then contract it. There is no cure and pretty much it will end up killing them. They still eat like a horse, but gain no weight, eventually they get weaker and weaker til they can hardly move and die the next day. Their feathers get dry, ruffled and a mess. When you pick them up, all there will be is a beast bone wrapped in feathers, no meat on them at all. The onset is very quick, usually by the time you notice the first ruffled feather, they are well into the illness and usually die within a week .
Does this sound like what she's doing?
Good thing is from what I have read and seen, it doesnt spread bird to bird, has to be consumed from the contaminated feed.
Now if the broken wing is bothering her, it of cousre could be the cause too.
But if other birds have died in a similar manor without ailments, my bet would be Avian TB.
