Most of the causes of death of birds, directly or indirectly caused by malnutrition (malnutrition) and stress. Consciously or not, we feed the birds with enough servings sometimes even exaggerated, but the quality is low, so it can happen deficiency (lack of a nutrient).
Tress problems in birds can be caused by poor feed nutrients, temperature changes rapidly, or both physical and psychological trauma. The cause of the disease due to deficiency or due to stress nutrisisi long run and cause birds to languish. At a time until the threshold of endurance ability, which often we found is "birds died suddenly!".
Instinctively, bird trying to hide his weaknesses. In fact, the bird is the most intelligent animal hide his weaknesses to be saved from his or stronger in the group. Bird was sick so good at hiding it as if healthy so that his enemies would not dare to attack him. However, if we are observant and conscientious once observed, is likely to know the characteristics of pain early bird.
Link: Ciri-ciri kenari sakit