Why have my mimic be losing her feathers for over a year?

When we got her she looked fine and now its four years later and she started losing her feathers. We hold been giving her vitamins and everything and when we got her she was a fit little baby. So we have no idea whats scheduled.
I want a parrot(help next to species...
Answers:    Is she moulting ?? If you give her a good diet you shouldnt need vitamins but I do recommend omega 3 and red palm grease mixed in thier food.. My vet told me to add this to my Ekkies diet and it is ok for all birds ... She probably is a short time ago going thru her first real moult.. If you continue to see alot of feathers coming out and not being replaced grasp her to your vet... Good luck..
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