Comments like, "You have a really kind heart and are obviously very caring and nurturing," would seem to imply, although I am certain it is unintentional, that to do otherwise (aka to euthanize) would indicate that the person was NOT kind, caring, and nurturing.
I rehome my healthy 'culls', birds that don't meet my goals but are otherwise healthy, but I won't pass along a crippled or unhealthy animal as I have no idea how the other person will be able to take care of them, and because I don't want to pass along my problems.
It sounds like this defect is, in the overall picture, likely not horrid. Unlike birds with stump legs that are easily irritated, or birds that can't walk, or birds that can't eat naturally, it sounds like it doesn't have any problems that would cause it undue distress or pain with proper care. In the case of the bird I am currently debating to cull or not, the picture is different, but based on posts on this thread and many others I am certain I would be told by many people (although perhaps not you, Wifezilla) not to cukll it. It's adorable, it's cute, it wants to eat and drink-- but it can't hold itself upright and cannot walk at this point. It seems as though one leg is stuck in a bent position and the joint is fixed. Sure, someone could probably put it in a cradle device and put water and feed under it's nose, and cuddle and hold it, but I don't feel this would be the best choice for the bird.
Sometimes, it's kindest to cull.