Comparatively speaking they could be whiter. Some breeds have really white earlobes. That seems more like some slight lack of pigmentation than a white earlobe? This is certainly not my specialty though.
No, it is pigment related. Chickens with red earlobes have a thin clear membrane. The red is blood you are seeing underneath. Chickens with white earlobes do not have a clear membrane there, it has white pigment in it so you cannot see the red blood. Some chickens have more white pigment than others.
Some breeds are bred to have white earlobes, some are bred to have red. That is controlled by genetics. Once you mix breeds it is still controlled by genetics but about anything can show up. It has nothing to do with egg shell color or feather color.
I suppose it might have something to do with calcium. To quote another user replying to a similar topic posted in 2010,
"I do think [earlobes turning white] has something to do with egglaying. I have a friend who had 2 Production Reds and their earlobs were almost completely "white" with just bit of red around the edges. They laid a jumbo egg everyday, so maybe that's why it's much more prevalent in their case." (Quote from jeremy)
In this case they are linking laying a lot of eggs with earlobes turning white. Could also be some other nutrient deficiency. Of course it could also be something genetic.
I would say temperature could certainly be the reason. Bring in the cold puts stress on the body, as does laying a lot of large eggs.
Earlobes changing color seems to be stress related. If this is true, she should be fine, especially once she is older and better able to deal with the cold. More body weight helps!