OK!
Nutritional Deficiencies
1. Protein (amino acid) deficiency..................reduced growth, rough feathering
2. Vitamin D deficiency.......................rickets, severe weakness in bones, soft pliable beaks and claws
3. Vitamin E Deficiency...................... uncoordinated gait...
Try sulmet or tetricyclin, it may be a bacterial issue...always quarantine birds exhibiting illness. And photographs can help provide you more help.
I hope it's not coryza, what I am trying to say
For someone who cares about birds, I wish you luck!