Why does the old hen have yolk in her stomach but not lay eggs, and there is a latent yellow egg-shaped meatball in her stomach! Please also know that friends mean a lot. ...

The hen is so fat that the eggs melt before they reach the bottom! Because there is a lot of suet in her spawning mouth, the eggs are blocked and can't come out. You can lose weight for her, just feed her some grass, green leaves and coarse chaff every day, not too much. They will lay eggs again in a month or so!