Maybe this question has already been covered, but if so I missed it. When those yellowish tinged feathers are molted and the new ones are grown in, are the new feathers also yellowish, or do they improve in color? That has happened with white birds I have raised that are exposed to too much sun during the grow-out stage. If so what you are dealing with is sunburn.
My birds don't get much direct sun and some of the LF silvers are more yellowish than what I had a few years ago. I do supplement their feed with shelled corn this time of year, but that isn't something new. I know the sun and feed can contribute to the "ting", but because some have more than others and the fact that all of them pretty my go back to my recent lines I believe the main problem is genetic.
A couple years ago I needed a LF male and Christina sent a very nice cockerel back to me that I sent to her as a day-old chick. Russ also gave me some nice cockerels, but they died. So, the cockerel from Christina was my main LF silver male breeder for the last two years. As he aged he became very yellowish. I sent him to Harry, earlier this year, but because he was so yellow Harry didn't use him. Some bird's feather color changes with age, so he may not have been the cause of the problem we are seeing with cockerels. It may be something that was picked up with one of the recent outcrosses with black and buff. I noticed today that the cockerel of mine with the more yellow is descended from the silver/buff cross, but he has a great comb. Perhaps the most silvery cockerel has the biggest and ugliest comb.
In the end it is just something that I believe we (or I) need to select against and try to breed out. Breed from the best, hatch as many as possible and cull heavily.