When I got Peter, he had an iodine deficiency, which was evident by his mild french molt. Budgies are the only birds that need to have iodine in their diets, and therefore have a real danger of becoming deficient. When I got Peter, I gave him an iodine block, and as he loved chewing on it, and that solved the problem, and got him on a schedule of only having a regular molt once a year. Later, I added spirulina to their diet, every so often, and that also helped.
Note: Never feed spirulina, unless specified by a vet, if you are also feeding pellets. When you first add it, go slowly, giving it to them one day, and then waiting a few days to see if you notice any changes in behavior. Then give it for a week in a row, and then wait a week to see if you notice anything. After that, just add it every so often, though you still will want to remember that you are feeding it to them in case you ever notice a behavior or health problem. I give it to mine in their mash, but you want to make sure it is not over 1 or 2 percent of the diet, so just a sprinkle.
Every late spring/early summer, I have to separate Peter from my other birds, as he gets extremely aggressive, to the point of attacking them and really doing damage. A week or so separated from them is usually enough to calm him down. I then have to put him back in, as during that whole week, they have been calling back and forth, and I have been sitting with Peter all morning and evening, trying to get him to eat enough. He does not do well with separation, needless to say.
Peter also always has trouble with his molt, getting very quiet, and losing weight. This summer he had even more trouble than usual with his molt, and it carried on for a long time, almost starting the french molt bit again. He had two iodine blocks in his cage, and I have throughout observed him chewing on them. However, his weight suddenly started dropping, and rapidly at that. He is normally 35 grams, and during a molt, more like 31-32 grams. He had molted many feathers, and they had started to grow in, but had stayed as pin feathers all over his body. His weight, in a matter of days, was down to 24 (holiday weekends, typical, isn't it? We don't have an emergency vet anywhere around here that I can find) Despite that illness, he was still eating like crazy, so crazy, he started attacking the other birds.
I had not removed him, because, as I said before, he does not eat very much when alone, and when he is sick, I have to leave him with Ava so she will take care of him, and he will continue to eat. This time, though, he really attacked Ava, and gave her a deep wound under her wing. I am not sure whether I should have separated Peter from the beginning, still, though, since that would have likely guaranteed his death. I guess it will always bother me. I separated Ava then, and after some intensive care, she has recovered and is doing well, though a bit slower, and is now back in with the tiels, in fact, being queen bee again. It is so cute to see how they all snuggle up together on the perch to sleep. My flock really take such good care of each other.
Anyway, back to Peter. He went to the vet, and through a round of tests. Because he is a budgie, and an extremely thin, sick one at that, there was only so much we could for him without too much danger. He did do several tests, and looked him over thoroughly, and he had no signs of any sort of infection or disease, or any test results that would indicate that. The final verdict - an iodine deficiency causing the thyroid glands to swell and block the absorption of food, or possibly a tumor, doing the same thing. The vet gave me a immune system supporter and an iodine supplement. I had already been giving Peter just babyfood sweet potatoes and carrots, with spirulina, as I figured that was the easiest thing to digest, and full of vitamins and minerals. I had also started giving him aloe detox and extremely high doses of probiotics.
After he hit a low weight of 20 grams, he started to climb again. He is now in quarantine separated from the other birds, as even though he did not think it something contagious, there is no way to tell for sure. His weight has gotten up to 30 grams, but then went back down to hover at 28, and has been there for a couple weeks. I am not sure of his age, as I got him as an adult with no history, though I know he is at least 5. So, it could be also a bit of old age playing into it, if he is older than I think.
After his final argument with Ava and the tiels, he seems to be doing fine on his own. I already had a close bond with him, and he would always come over to give me kisses or to sing with me when I came in the room. Now, however, he is even sweeter, and is so happy to get out, and play around, and comes running over to hop on my finger. Every morning, I uncover him when I get up. After talking to him for a minute or two, to give him a chance to wake up, I open the door, and he comes hopping forward to get on my finger to be weighed. He is so sweet, to jump on the scale, and look at me with his head cocked while we wait for the reading. Then he gets so excited to run back in his cage, and check out his food dish to see what food he has for the morning. I can only hope that whatever his issue is, it resolves soon, as I can not imagine loosing him. I think I will get him back in for a check up in a bit, to see how he is doing now, and if there is anything else we can do.