I did have a look at my chicks feathering but they pretty much just developed in order of who hatched first. Non were particularly more developed or had longer feathers. The first hatched had the most where as the last hatched had the least

we done feather sexing on some of our other breeds before with success but not my Silkies. They're a pain...but still lovely!
All of my whites developed quickly compared to my partridges though. The partridges are tiny and have hardly any feather development. Maybe that's something to do with the colour.
I'll look forward to seeing what you get!