Thanks for the input. (and Mrs. Bird brain & Timmy, thanks. Just thanks
.)
I'll crawl out of my hole and respond.
We switched feed about 2 months ago to a higher protien feed that was recommended for show birds. I was simply washing her to get ready for the show, like we usually do, and struggling this time to get her white. We try to wash early in the week so that the natural oils have time to come back and give that pretty sheen.
The Tide with bleach was reccomended by a breeder and judge who's been showing white birds for 20+ years.
Their bedding is pine shavings and the surfaces of the coop have been painted so no exposed wood there. They free range on 2 acres of grassy yard and a sandy/dirt area that used to have a pool is a favorite dust bathing spot (as well as most of the flowerbeds, but that's just chickens for ya!)
For the record: I put about a half cup of bleach in 5 gallons of rinse water, she was being swished around in it for, um, a minute or less? And I used a toothbrush to stroke/paint bleach on her tail feathers. It didn't get on her skin, it got on mine because I was holding them out to brush the toothbrush acrsos them. I did not dump a bottle of bleach on her and work it into her skin.
I went to the store and bought the expensive shampoo for white breeds, and a special (and expensive) conditioner spray. Used that last night. Didn't help with the yellowing.
Unfortunately, I think the poster who said corn was the culprit is right. I suspect that the higher protien food, had a higher corn content and that caused the problem because the yellowing wasn't as bad 2 months ago *sigh*. And the yellow is more pronounced than even at the end of summer last year, so I'd rule out the sun being the culprit. It's irritating because I limit the corn intake and sun exposure just because she's white and I know that is an issue.
I just wanted to know if there was an idea out there I could try. That's all.