The best is to hatch a clutch yourself and be able to watch the feather growth of each one. Female wings almost always grow rapidly, along with tail feathers, and then shoulder feathers. Judging within the same breed. Your boys will still be looking bald in comparison to the gals. This did prove very wrong for me ONCE with a Barnevelder chick that feathered in slower than the pullets and the roos, and turned out to be a pullet. I guess nothing's 100%? The combs and waddles are obviously better signs, but who wants to wait that long??
Tell me about it! I keep reading all this stuff online and from people who have had birds that look like mine to see if I can figure anything out, but it's difficult. I've seen people have opposite ways of telling what bird is what, and each way works for whoever has it. I don't know what to think.
That Marans is like 4-5 weeks old. Wyandottes grow really fast actually, so they have outgrown their older broodmates. I think that Marans you got was from a pullet egg if it's the 1 I'm thinking of so it started out about half as big as it's hatchmates & just hasn't gotten caught up yet. The black OE you had picked out & traded for it was it's hatchmate. The OE is still a good bit bigger...LOL
Oh man. When I got home I saw the size difference, and was like, "Wait. I thought this bird was older." I was so confused haha. And I see what you say about the Wyandottes. They grew fast and are as big as the blue I got from you despite being a week or more younger.
The blue is maybe 2 weeks younger than the porcelain & the porcelain is from right before Easter so she would be 8-9 weeks old, the blue would be 6-7 weeks & the FBCM is 4 weeks (just went back & figured out hatch dates...LOL). I constantly have stuff hatching so gets a bit hard to keep track sometimes.