The cuckoo Marans that I used to raise were cleaned legged. All my Wheatens have feathered legs.
Any possibilty that you put in one of your cuckoo eggs? Sounds like it could be a cuckoo or do you have any BC Marans?
Here are some of my BLRW chicks
Your wheaten Marans chicks should have feathered feet too altho not as much as the cochins.
Wheaten Marans chicks are the yellow ones: