My chicken who is quite old, has just come out of her coop with a large lump on the side of her neck. I picked her up as recently she had hurt her feet so I check on her regularly, and the lump moves from side to side. My mum helped and gently messaged her neck to see if it was a knot in her neck and she started to throw up yellow goo, (shocked because chickens can’t throw up). I haven’t seen her eat or drink and I’m not sure what to do, please help!!