Molt can cause paleness sometimes too. Are any of them laying? Hens that are off laying for the winter (shorter daylight hours) will sometimes get paler. With ex-bats who have lived in confinement, it can take a while for them to look better and healthier. You may want to switch to a flock raiser or all flock type feed that will be in the 18% protein range, and offer oyster shell in a separate feeder all the time for those that need it. The higher protein may help with feather growth, which takes a lot of protein.