Parrots are masters at concealing their illnesses until they get critically ill. The following are some of the first indicators that your favourite pet is sick:nnalterations in eating and drinking habitsnLethargic behaviour, vomiting greasy-looking feathers, and faeces that have changed.nIf you suspect your parrot is sick, get them to the vet as soon as possible. If you have additional parrots, make sure they are kept isolated from the sick one.