Hi!
What you are seeing is not uncommon and may be related to "anting" behavior.
There are two types of anting behavior - passive and active.
In passive anting, a bird may sit on top of an anthill or a line of foraging ants and allow the ants to circulate through the feathers.
In active anting behavior, a bird picks up an ant (or it can also be other things, but usually these things are somehow aromatic or acrid - an example of another item wild birds have been seen anting with are lime peels) and rubs the ant through the feathers.
Particular types of ants seem to be preferred by birds that ant, and these ants spray formic acid as a defense mechanism. It is thought that the formic acid is somehow beneficial to these birds, possibly as a parasite repellent, but this is speculation.
During active anting, some birds may hold the ant close to the base of molting primary or tail feathers, and others have been observed to rub the ant over entire feathers. Sometimes anting behavior is noticed more after a thunderstorm, which may indicate that it is somehow stimulated by an acrid smell in the air....sometimes anting behavior seems to be connected to molting.
If anting is connected to parasite control, it may be possible that nesting or hormonal females might do it as an instinctive way to control parasites that might be present in the confined space of a nest cavity....again, speculation.
Of course, we would not want to use any kind of acids, etc with our birds, but it may explain something about this type of behavior.
The behavior may also be a way to keep clean....like a dust bath, only using what is available...dry food items.
While wild Eclectus have not been observed to perform anting behavior, it seems that it may be that they do, since many Eclectus owners have noticed this kind of behavior. While our male SI Chardy will occasionally preen using his dry food mix, we typically see the behavior more from our female SI, Cabby. She will preen with anything dry, but prefers to use dried hot red peppers (remember the above about aromatic or acrid smells stimulating the behavior? maybe there is a connection...maybe not). She will pick up the pepper and rub it over her feathers, under her wings, and even place pieces of the pepper into her feathers and shake them through.
It might be a good idea to try to add some small, dry hot peppers (I think I have seen them sold as "parrot peppers", for example) to her dry food mix. If she is trying to perform "anting" behavior, she may appreciate the acrid, aromatic peppers.
But keep in mind...by anting with hot peppers, her beak, feathers, skin and feather dust will get hot peppers on them! This is not a problem, but you might sneeze or get hot lips if you breathe the dust or kiss her
I hope some day we may be able to report more definitive information about what the behavior means, but for now, I would say it is normal, and to just provide for it (with the dry peppers).
We hope this information is of help to you.
Al and Mary
Cabby and Chardy (SIE)