To complicate things the cochin on the right in the last image (mango) is a really slow developer. S/he didn't have feathers at all for the longest time after Harriet (cochin on the left) was already fully feathered.
I have two partridge cochins who are about ten weeks old. One is growing much faster than the other but both have waddles and large combs. Are they both roosters? I also have a mottled houdan that I got from a straight run. S/he has a really long tail so I've suspected possibly a roo...