Parrot looking thin

Why Is My Parrot Losing Weight? 9 Common Causes

It is difficult to see physical signs of weight loss in parrots until they start looking emaciated. This can be worrying because losing weight is often a cause for concern. 

Unexplained weight loss in parrots is most often caused by beak injuries, dietary changes, or underlying health conditions. Sometimes, the parrot may lose water weight due to diarrhea. Parrots also lose weight during the molting season. In any case, a noticeable drop in your parrot’s weight warrants a visit to the vet. 

How To Tell If Your Parrot Is Underweight? 

The standard way to check if your parrot is underweight is by weighing it on a scale. However, most people do not have a scale and the ideal weight range for parrots can vary significantly between species. 

There is an easy way you can tell if your parrot is underweight without a gram scale. It involves feeling your parrot’s breastbone and assigning it a keel score. The keel score is a measurement used to evaluate a bird’s body condition and overall health. 

Here’s how you can check your parrot’s keel bone:

  • Hold your parrot with a gentle restraint.
  • Run two fingers across its chest and locate the breast bone.  
  • Feel the breastbone and score your bird based on how sharp it feels.

Based on your assessment, assign a keel score. If the breastbone felt too sharp while touching, it means your parrot is seriously underweight. On the other hand, if the bone is easily located but doesn’t feel too sharp, your parrot is in the ideal weight range. 

What Causes Sudden Weight Loss In Parrots?

Below are the causes of sudden weight loss In parrots:


Parrots maintain roughly the same weight throughout the year, except during the molting season. It is normal for parrots to lose weight during molting. 

Molting is a physiologically demanding process for parrots that involves the shedding of old feathers and growing new and vibrant plumage. According to the Searchable Ornithological Research Archive in captivity, adult birds often lose weight during a molt.

This process puts an increased demand for energy and nutrients on the parrot’s body which results in rapid weight loss. This type of weight loss is temporary and the parrot usually attains its normal weight once the molting process completes. 

Most parrot species molt twice a year, which means it’s entirely normal to observe these weight changes during those periods. However, you can make the process easier for your parrot, by providing them with a balanced diet and some extra care to help them through this time.

Recent Change In Diet

If you’ve recently made a change to your parrot’s diet, it could be a reason for sudden weight loss. Parrots can sometimes be finicky when it comes to food. So if your parrot is not eating enough food, it can make them lose weight. Many parrot owners struggle to get their parrots to eat healthy because they would only eat their favorite parts and leave out the rest. 

If you’ve had your parrot on a pelleted diet from the start this shouldn’t be a problem, but if you’re just now introducing them to pellets, it may take some time for your bird to get used to it.

Parrots that are addicted to seed often suffer the most from a drastic change in diet. They will refuse to eat anything but seeds and sometimes even starve themselves. This is why it is best to make slow adjustments, rather than completely switching up the parrot’s diet.

Difficulty In Eating 

Injuries to the parrot’s beak or foot can prevent it from eating properly. Parrots make use of both their beak and feet to grasp and eat food. So if the parrot feels discomfort in using its feet or beak, it will eat less than usual. 

Crop infections and oral lesions can also make it difficult for parrots to swallow food. If you notice your parrot drooling and opening its mouth more often, it could indicate injuries inside the mouth. 


Weight loss is the change in total body mass, often through fat and muscle mass. However,  weight loss can also occur as a result of changes in body fluids. If the parrot’s body loses a lot of water over a short period of time, it can appear as though it suddenly lost weight. 

Diahrrhaea can cause watery or loose stools, which can result in the loss of fluids from the parrot’s body.  In most cases, diarrhea resolves itself within a day or two. However, if diarrhea persists for a longer period, it can deplete body fluids and vital nutrients which can lead to sudden weight loss. 

Foods that can cause diarrhea in parrots:

  • Dairy products 
  • Sugar 
  • Unhealthy human food
  • Watery foods like watermelon


Polyuria is a condition in parrots that refers to the excessive urine content in the feces. It is often confused with diarrhea, as it looks quite similar. However, diarrhea is characterized as loose feces whereas polyuria is the presence of more urine. Recognizing changes in parrot poop can also help you understand why your parrot may be losing weight.

A parrot’s dropping consists of feces, urates, and urine. During polyuria, the parrot will pass more urine in its waste both in terms of frequency and volume.

This condition can result in weight loss through dehydration or loss of water from the body. It can also point to other health issues like kidney disease or diabetes.

Stressful Events

Stress can manifest in various forms in parrots. When a parrot is exposed to stress for any length of time, it may feel disconnected from its environment and become depressed.

This can make it lose interest in any sort of physical activity and sometimes its food. The parrot may refuse to eat it despite you trying your best to feed them. 

Parrots can be quite stubborn in this way, which can lead to drastic weight loss over a short period of time. The parrot’s condition may not improve unless an effort is made to remove the stressor from the situation.

Intestinal Parasites

Various types of internal parasites can live inside your parrot’s body and cause it to lose weight unintentionally. These parasites can also diarrhea and vomiting in your parrot. Intestinal parasites can infect parrots due to poor husbandry and generally an unclean household. 

These parasites can transmit themselves into the parrot’s body if they’re accidentally carried into the house. Symptoms of intestinal parasites in parasites include diarrhea, lethargy, and unexplained weight loss.

Iron Storage Disease

Unexplained weight loss in parrots can sometimes be attributed to Iron storage disease. It is a disease caused by the accumulation of iron in the blood. It usually occurs in parrots that are fed an iron-rich diet.

A diet that is also high in Vitamin A and Vitamin C can increase the absorption of iron in the blood. This is why oversupplementaion can be extremely dangerous to parrots. 

Renal Disease

The kidneys perform the important function of filtering waste from the blood. So when the kidneys aren’t functioning properly, it can cause problems like your parrot losing weight unexpectedly.

Other signs of kidney disease in parrots include:

  • Increased thirst and urination.
  • Loss of appetite
  • Changes in poop
  • Lethargy.
  • Depression

Other Underlying Illnesses 

A sick parrot will often lose its appetite. There can be various other illnesses that can make a parrot lose weight unintentionally either through a loss of appetite or by the body’s increased energy expenditure to fight the infections.

When Should You See A Vet About Your Parrot Losing Weight?

There can be so many causes of weight loss in parrots that it can be hard to know the exact reasons without a proper diagnosis by a vet. Some cases can be related to diet and behavioral issues and can be resolved over time. However, if you suspect your parrot is sick, you should take them to a vet.

The vet can check the bird’s weight and perform a complete evaluation to identify why your parrot is losing weight. Based on the tests, the vet can recommend appropriate treatments and guide you on how to help your parrot maintain a healthy weight.

How To Promote Weight Gain In Parrots?

In captivity, parrots are at a higher risk of obesity than becoming underweight. However, being underweight can also be a dangerous condition.

Sometimes parrots can also have trouble gaining weight for non-medical reasons. In such cases, a weight gain diet can help them in achieving a healthy weight. Here are some steps you can take to help your parrot put on some healthy weight:

Address Underlying Issues

Before trying to modify your parrot’s diet to make it gain weight, it is important to first recognize the cause of an unexpected weight loss. A sudden weight loss is almost always related to underlying health conditions. 

It is hard to find out what may be causing the issue from signs and symptoms alone. So a visit to the veterinarian will be required to identify the exact reason for your parrot’s weight loss. The vet will then be able to advise you on what measures you can take to help your bird get back to a healthy weight. 

Increase Calorie Intake

Parrots can actually gain weight quite easily when they do not have any health issues holding them back. Increasing the frequency or quantity of your parrot’s meals can help them grow much faster. 

But be careful not to overdo it. Parrots do not know when they’re full so they can eat themselves to become overweight if you’re not careful. You need to increase the calorie intake in a balanced way so your parrot does not actually get fat.

Dorson Joseph
Dorson Joseph

I'm Dorson, a bird enthusiast who's had a lifelong fascination for the avian world. I am a parent to my beloved Senegal parrot and budgie, which has deepened my love for avian creatures and taught me a lot over the years. I co-run a bird store and care center with my friends, where we work with experienced professionals to care for our flock. Now, I find great joy in sharing my knowledge with others, hoping to assist fellow bird keepers and enthusiasts in understanding birds and helping them live happy lives.

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