Do not feed budgies like people
Diarrhoea is common when birds are given crisps, bread, tea, cake, etc.—fat, salt, yeast and starch are unsuitable. In nature budgies mainly eat seed; base the diet on appropriate bird food.
Check droppings early
Even if the bird looks well, check paper under the cage 1–2 times weekly. Early diarrhoea is easier to treat.
During diarrhoea
Extra greens can worsen diarrhoea. Avoid random medication—see an avian vet. When healthy, offer tiny portions of safe vegetables instead of watery lettuce or cucumber.