A preening gland question

[Hezz]

This question is aimed more at the larger scale breeding members of our forum.

Some may remember one of my hens, Smudge, has a problem preening gland, this is the link to the past thread:
budgerigarsforum.proboards.com/index.cgi?board=budgiehealth&action=display&thread=3727

I have been leaving her be, trying to give them all an hour or more of dappled sun most days (so on average, probably 4-5 days a week) but lately as it has been so hot, I have been spraying them more regularly and giving them baths to splash about in - although Smudge isn't a bather. And I have noticed that she doesn't shed water the way the others do, her feathers seem drier and fluffier than the others (and always have, but to me there seems a subtle difference).

My question is this: if the gland is not producing the oils (or she is not able to access the oils because the growth has distorted the gland) is this a health issue for a captive budgie? She seems still to be in good health (a trifle over-weight, but maybe even losing some, due to more exercise). Obviously her feather-health may suffer to some extent, but to just what extent, and how about her overall health?
Has anyone had this sort of problem, and dealt with it?

[barrieshutt]

this will prevent her from extracting vitamin D , supply calcivite 3 times per fortnight

[Hezz]

Thanks for that Barrie. Will get some tomorrow. Will this be an ongoing dosage, or should I give it for a while, and then give her a break? I add "The Good Oil" to their seed all the time, but obviously this isn't enough to supplement her Vit D deficiency. I trust the calcivite is not going to be a problem for the others if they get it as well?