My conure is losing underfeathers on its belly. Molting or sick?

This actually looks like normal molting and not a condition causing feather loss. I would be worried about lice, mites, skin disease, or feather plucking if there were bald areas, but the under feathers are still there. The fact that there are still some feathers covering the skin indicates that a primary problem affecting the feathers is not present. I expect that his feathers will look more normal after one more month if of this is due to molting. If he happens to get bald areas, or is not looking better after a month, then it would be best to have a vet examine him for the problems mentioned above. I hope that helps and all is well with Maggi. I also wish you luck in getting through that brutal summer. I've suffered through one summer there and was happy when monsoon season finally came.

The photo is incredibly blurry so it's hard to see if there is crusting or any new feathers coming in. Feather loss around the eyes may be molting related if he is molting elsewhere, however eye issues, infections, mites, etc may also cause scaling around the eyes or feather loss. If you can't see new feathers coming in, the eye is itchy or bothersome, or it worsens, seeking veterinary care in person is best.

Baby birds can lose feathers in what looks like a molt as their adult feathers come in. If she is molting, you will see new feathers, called pin feathers, sticking out of the skin (they look like little needles). If she is otherwise healthy and active and on a balanced diet I wouldn't be too concerned, however you did mention she is a bit lethargic. If she is losing feathers and isn't growing in new ones, and remains lethargic or begins to decrease her eating/drinking habits, have changes in stool, etc, then seeking out an exam in person is best to rule out any issues such as parasites, illness, nutrient issues, etc that could be causing her symptoms. Keeping her eating and drinking, warm, and away from any other birds that may pick on her if she is ill can also help until you can get to a vet.

If Bobo is otherwise happy and healthy, he could just be molting. This is a normal thing that happens when your bird sheds their old feathers and replaces them with new ones. You will likely see "pin" feathers, or feathers that look like little pins sticking out of the skin in the places where old feathers were lost if this is the case. If, however, Bobo is itching, there is redness, new feathers aren't growing in, or he seems ill or upset, it could indicate something else such as parasites, skin issues, etc, that should be checked out by a vet.

Thanks for adding in a photo! From the photo, it looks like Meenu might be molting! This is normal in all birds, and happens when they replace their old feathers with new ones. Baby birds will also have a molt as they reach adulthood, losing their soft downy feathers (the wispy ones in the picture) and replacing them with their adult feathers. It is very normal for colors to change somewhat during a molt as brighter colors come in, and the feathers may fade some with time as well. As long as Meenu is otherwise healthy and happy, it isn't anything to be worried about. To see if your bird is growing in new feathers you can look for pin feathers (small like needle-like things poking out of the skin). Making sure Meenu is on a healthy balanced diet can help make sure she has a good molt and grows in healthy new feathers.

Feather loss can be from any number of things, so finding the underlying cause is best. Molting is a normal loss of feathers that occurs 1-2 times a year and all the old feathers are replaced with new ones. You will see "pin" feathers appearing on the skin (look like needles or pins) to indicate this is a molt and new feathers are growing in. Making sure Mithu is on a balanced diet can help ensure he grows in new feathers. Skin issues such as parasites, infections, nutritional issues, etc can also cause feathers to fall out. Treating any visible wounds, making sure Mithu is on a balanced diet, and using a mite spray to treat any external parasites can help. Illness can sometimes cause feathers to fall out either due to a lack of nutrition or from the illness itself. If you can't find an immediate problem, having a vet examine Mithu is best to rule out any illness. Boredom and stress can also cause feather plucking, which may make it look like the feathers are falling out. Making sure your bird is kept in a quiet, stress-free area away from noisy pets and people, and providing lots of enrichment such as toys to play with and chew on, fun treats, and time spend together can help. In some cases, an Elizabethan (e-collar) may be needed to break the behavior if it has become a habit.

The "stems" you are seeing may actually be the pin feathers that are coming in as she loses her old feathers and the new ones come in. They are called pin feathers as they look like little pins sticking out of the skin. As the feather grows and erupts from the skin, it will turn into a full feather instead of just looking like a "stem". This is 100% normal and healthy! Molting can take several weeks to a month or two depending on the bird. Making sure Wiggy is on a balanced diet can help ensure her new feathers grow in healthy. As long as she is otherwise acting healthy and normal I wouldn't be worried. If you do see any signs of illness, the new feathers don't grow in properly, or she seems in distress, speaking with your vet is always best.