My 1-month-old cockatiel chick vomits after eating. What's wrong?

It's possible you could be overfilling his crop, causing him to regurgitate up some of the extra food. Checking his crop (located on the neck, it will feel like a little balloon when full, or be visible if his feathers haven't grown in) can alert you if he's full or not. If it's full, waiting a bit to feed him again or decreasing the amount fed and just feeding more often can help. If his crop is always full, or he is unable to keep any food down, having a vet take a look to rule out issues such as obstruction or illness is best.

You need to take him to an avian vet specialist as he us definitely not fine, regurgitation is usually caused by a crop disease, it could be yeast, bacterias or a foreign body. the vet will take a crop and fecal sample to check for an infection first, if he can't find one the next step will be an xray.

Thanks for reaching out about Rue and including a photo. Provide heat support in the 80-85 F range, for aid. Remove perches and place a soft towel on the bottom of the cage. Only provide small amounts of water to drink. This could be a crop infection (bacteria, fungal, yeast), obstruction, toxicity and more. See your veterinarian first thing in the morning to assess and provide a diagnostic/treatment plan. Good luck.

Thanks for reaching out about Loki and including a photo. Repeated regurgitation is concerning. Ingested foreign bodies or toxic causes are common. If it persists, a veterinary visit is recommended. Good luck.

It does sound as if Garf is pretty ill and needs to be seen by a vet in person. Sour crop can be caused by a number of things including infections, obstructions, etc, and if he can't keep any food down and is vomiting, vet care is needed to clear the crop and get him started on medications. Your question cut off, however, if you are having trouble affording vet care, this site may help give you some ideas so Garf can get the help he needs: https://www.humanesociety.org/resources/having-trouble-affording-veterinary-care

Those symptoms are mainly symptoms of nausea, it's common in birds suffering from a gastrointestinal infection, yeast (candida) being the most common cause (but not the only one). you will need to take Nazi to an avian vet specialist ASAP in order to get it treated.

Vomiting is a very concerning issue, and if Cutie is unable to keep any food down, is losing weight, or is otherwise showing other signs of illness, seeking veterinary care ASAP (and separating her from your other birds into a hospital cage) is best. Infections, GI issues, parasites, crop issues, etc can all be possible causes.