Scales are one sheet and thus, for example, snakes shed the whole skin in often one piece. So changes in the genetic code have to happen to change this sheet of scales into individual highly complex feathers.
Read more here:
“A further difficulty pertains to explaining the origin of feathers. If, as is conventionally maintained, feathers evolved from scales, one has to posit some kind of Darwinian explanation for their evolution from perhaps frayed scales, which must include some kind of genetic basis for every step from frayed scale to fully sculptured feather complete with its many specialized features. Based on what we presently know of the genetic mechanisms, structure and molecular composition of functioning feathers, the proposition that these structures evolved from frayed scales may now reasonably be regarded as ludicrous.” (https://evolutionnews.org/2011/10/fact-checking_wikipedia_on_com_1/ )
Maybe Feathers didn’t evolve – in other words, evolution requires more faith!