budgie with stooped neck
please can anyone advise why my budgies neck has stooped ? he is no longer able to lift his head to a normal position, and seems to be getting worse over time.
what is causing this? as I do not think he has been injured ? can it be corrected? is it an illness or genetic? I ask as his sibling is also starting to drop his head, and I don not know why, or if I can do anything to help / prevent.