As far as floatation goes ...
... it is my experience that the natural oils do contribute to better floatation than I get with a "treated" CDC feather.
The CDC that I've gotten from a couple hunter friends is far superior to even the best CDC from Trouthunter. Much better floatation for much longer. I fished one Harrop's Henry's Fork Caddis tied with CDC from a hunter friend on a small spring creek down in the Central Mountains of Idaho and caught about 35 trouts ( smaller bows and brookies ) over the course of a couple hours before the fly refused to float. ( While the number of fish caught was unusual, the performance of the fly was not. ) Nothing was required to dry the fly, other than false casting or just blowing on it.
On the other hand, I have tied some CDC loop wing style flies with premium CDC from Trouthunter, and they were hardly fishable. Tied very similar CDC loop wings flies for the March Brown and Mahogany hatches with CDC from my friends and did very well with them.
John