7 Signs That You Have a Sick BirdBirds do not generally require vaccinations but routine health evaluation for weight loss and other signs of impending illness should be performed every six months. Birds as flock animals are symptom hiders until they have a severe illness. While this is a good trait so the flock will not reject them, it is a terrible trait when caretakers are trying to detect illness. Large birds, larger than a cockatiel should have yearly blood profiles. Often blood profiles are the first indication of illness.