My barred rock hen has been moulting the last few days and today we noticed a large lump at the base of her belly. She is eating and acting normally, but has not been laying. Not sure if the moulting is due to the lump, but she is growing back new feathers while losing them at the same time. The lump is soft to the touch, but firmly formed (rounded) and is about the size of half a tennis ball. Any advice would be most appreciated - not sure if it is something terminal or requires medical attention.