Tekkei

Tekkei (鉄てっ鶏けい, "Iron Chicken") was a great bird daiyoukai literally the size of a mountain who was the mother of Princess Abi and queen of the demon birds. She was also part of a group of bird demons of the Netherworld.

Tekkei ate the leader of a rival demon tribe in the area. That particular species turned out to be toxic and she was badly poisoned, forcing her to rest inside of her bird demons' mountain nest with only a hole in the mountain for her to see and communicate with the outside world.

(Source: InuYasha Wiki)