Straining repeatedly without laying an egg
Sitting or standing hunched up
Tail bobbing with each breath
Distended or swollen abdomen
Penguin-like stance with legs held apart
Lethargy or weakness
Loss of appetite
Reduced or absent droppings
Frequent visits to the nesting box with no egg laid
Visible discomfort when moving or being touched
Labored breathing
Pale comb and wattles
Drooping wings
Sudden decrease in egg production