Pictures Is my female tiel plucking?

[cgormez]

Hi there, we have a female tiel approx. 6-7 months old and we are suspected from plucking.
She shares the same cage with our other cockatiel, who is one month older than her, so she is not alone. The dimensions of their cage are 88.5 x 88 x 159 cm. They are let out for two to three hours daily, and since we’ve been at home lately, there doesn’t seem to be any source of stress. We regularly give them multivitamins and B vitamins. We also have iodine pickstone in their cage but we’re not sure if she is interested. What could be the problem?

 

[Finchbreed]

I am assuming they have a varied diet of mixed seeds. Milletts, sunflower etc?
Combined with a regular selection of greens, seeding grasses, dandelion etc?
Plucking is sometimes seeking something that is missing from the diet and sometimes stress.