those type of loose feathers will molt out normally .The Marans SOP states that that plummage should be moderately tight and smooth textured. You may recall that we have mentioned tight or loose feathering in some of our critiques. I thought I would share an example of loose feathering (undesirable) in one of my growout pullets. I will wait until after her final juvenile molt but I suspect that this fault will not improve. She will most likely end up in my layer pen unless she lays an exceptionally dark egg then I may consider single mating her then culling hard for loose plumage. In the pics, notice how the feathers are fluffed outward from the middle of her back towards her tail.
let see when she is fully grown .