Sounds like the possible causes for the colorless yolks means you will get more. If not cappilaria worms, like sumi suggested, I suppose it could be some sort of metabolic problem.
I found this, but it doesn't explain why you'd suddenly get a super white yolk. Do you have a new layer? I'm wondering if the same hen can go from laying yellow yolks to cream.
http://www.npr.org/sections/thesalt/2013/07/12/201501977/help-my-egg-yolks-are-freakishly-white
Yolk color is mostly diet. The carotinoids in green leafy foods and other types of colored vegetables make the yolks darker. It is generally a sign that the birds have a healthy diet and the eggs tend to be healthier too. A diet high in greens and grasses supposedly lowers the cholesterol in...