Skipped molts - trying to figure out why

[DonyaQuick]

I have two black olive eggers that are nearly two years old now and never molted over the fall/winter. Same age but unrelated siblings all molted by February and did full molts (those siblings were supposed to be olive eggers too and were in the same bin, but they lay regular brown eggs). For a while I held out hope the two olive eggers were just going to do it late, but it's a good way through spring now with no sign of it an no sign of stopping laying either, so I'm probably hoping in vain now.

I'm trying to figure out what might have led to them skipping molts in fall/winter and how to avoid it in the future if it's something within my control...or if it's more likely something genetic, since these two birds are from the same batch from the same hatchery. I have 22 adult birds right now and none of the others have ever had this problem. A couple times in the past I've seen partial molts that were a start/stop/start situation due to weird weather, but never just fully skipped molts like this in birds >1 year old.

For both olive eggers:

• Eggs have good shells (no soft shelled eggs, etc.)
• They never stopped laying eggs. They each lay almost daily and did so through the entire winter.
• Stumps of feather shafts are left in pores.
• If I remove a feather shaft manually, the feather will start to grow back in a couple weeks but will "stall out" about halfway through growth, fail to fully develop, get damaged, and eventually lead to another stump (although a different kind of stump than the original feather; damaged-beyond-repair pin feathers leave thick hard nibs).
• They are not picking their own feathers and preen normally as far as I've seen. The feathers have just slowly gotten worn over time. I've watched bits break off here and there from normal activity.
• Skin shows no sign of irritation and birds are not itchy or picking at theselves, so I do not think it's depluming mites. They have been heavily inspected many times for other kinds of mites or other ectoparasites.
• I sit with the flock daily and inspect these two birds frequently for any sign of proper molting, so they most definitely did not sneak it past me. All of their remaining feathers are a year old now.

Environment/feed:

• Feed is 20% all flock with calcium on the side.
• I have tried vitamin supplements in feed and later via water.
• I have tried offering extra protein.
• There is no artificial lighting in the coop.

This is one of the olive eggers (the black one). I can try to get better pictures of both birds and without saddles if it would help; but they just look like your typical rooster-damaged hens that need to molt. The barred hen is one of the same-age, same-bin-at-the-store siblings.

 

[oldhenlikesdogs]

I would remove the rooster if you aren't breeding. That's a lot of damage. Sometimes other birds will pluck the muffs off other birds. You may be dealing with a feather picker.

Molts sometimes can be so slow you don't notice, but if the hens continued to lay than they probably didn't molt. Are you providing extra light? Or is there light shining in the coop at night? How old was the hen last fall? Fully a year old?