we have euthanized chicks and chickens before, if they are injured beyond help or affected in a way that is clearly not fixable or reversible. However, we let “it” run its course when it is not clear that they are in such a desperate situation. In that case, sometimes they improve.
since she has never been as active or growing nearly as well, she may just have an internal issue that you cannot fix. But she might be able to live that way for awhile. It is a personal decision as to when she’s too far gone.
If you choose to euthanize, cervical dislocation is a usually bloodless way to euthanize a chicken- separating the brain from the spinal column, and is sometimes referred to as the broomstick method. On a small chick, sharp shears are quick and easy (but involves a small amount of blood). Getting the chicken calm first is best for all. So, a darkened or low light area that is quiet works well. You may choose to do this after they have settled down for the night and they are naturally more calm (particularly if you keep the light low).
Could be the same with yours.
