Why is my pigeon losing feathers, shivering, and has new growth?

Molting time is different for each individual bird, so yes, molting is possible if it is that time for Sheephony. You may see new feathers, called pin feathers, growing in to replace the old if this is the case (they look like little pins sticking out of the skin, hence the name). Other potential causes of feather loss can include nutritional issues, parasites on the skin, infections, illness, etc, so if she seems otherwise unhealthy or ill, or you aren't seeing new feathers growing in, scheduling an exam with your vet is best. In some cases, birds will also pluck feathers if bored or stressed, so adding some enrichment and making sure Sheephony is kept in an area with low stress may help as well.

It is possible Penny is molting. This is normal and is the process of losing old feathers while new ones grow in. You may see pin feathers, or small feathers that look like little pins sticking out of the skin as they grow. It often looks like a mess because some birds tend to lose a lot of feathers all at once, while others have a slower, gradual molt. As long as she is otherwise healthy and active, making sure she is on a balanced diet to ensure good feather growth is best. If she seems ill or new feathers are not growing in, it could indicate she is ill, has some mites, or another skin condition which should be checked out by a vet.

Shivering is unfortunately a general sign and not an indication of anything specific. It could be that your bird is cold or nervous, and moving her to a warmer, quieter location may help reduce stress and help her regulate her temperature. If she has other symptoms in addition to shivering, such as not wanting to eat or drink, changes in stool, sleeping all the time, etc, then this can indicate illness and should be checked out by a vet in person if she doesn't improve after a day or so.

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.

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.

Without photos or more info it would be hard to say. it could just be normal molting of the older feathers, and the new ones haven't grown in fully yet so they appear shorter or rough until they are fully grown. Some issues such as health problems or nutritional issues could also lead to stunted growth of feathers, so ruling out any issues with your vet if the problem doesn't resolve is best.