This is a very difficult subject, and no one with compassion will find it easy. But, as an old nurse, I have to say that burning has got to be extremely painful. The shears, or the home made euthanasia chamber (with baking soda/vinegar mix I believe - right?) would have to be more humane. Also, the chick in the picture above, almost looks micro-cephalic - as though perhaps his brain didn't fully develop. If your chick is able to eat/drink on his own, he might be capable of surviving. The question is are you capable of caring for a special needs pet that would need extra time and attention. There's no right or easy answer, and I'm sure you will follow your heart and do what is right for you. Good luck.