The barring gene is on the Z chromosome, and the mother hen has only one Z chromosome. So, if the dad has no barring at all, but the mother is barred, then all the male chicks will be barred, and the female chicks will have no barring.
Here is an example (source)
Hey everybody, want to share a story to warn you all. My aunt has always been into poultry and meat birds. Last year she started preparing 'sushi' with raw meat from the birds she culled. She became addicted and was eating it almost daily until last month. She got really, really sick from food...
People told me I'd never be good at poetry because I'm dyslexic.
But so far I've raised more than 300 chickens and other domestic fowl and none of them died.
Green diarrhea can also result from a bacterial infection like Pasteurella, which thrives in colder seasons. Are there any rodents or other animals entering the coop? You might want to isolate her in a warm, dry place to prevent transmission.
Off-topic: what an amazing coop!
If you're interested in black breeds, you can also look for a mystic onyx. Its a relatively new black crossbreed registered by Hoovers as an alternative for the ayam cemani. It's also a decent layer.
If she has green runny droppings and reacted well on tylan I would think of fowl cholera, a bacterial infection. It's also known to reappear when treatment stops and when the bird catches the bacteria it's there to stay. Are you still giving the antibiotics?
Reading your post, I was initially thinking of an eclipse molt. Some chickens, like junglefowl and gamefowl, have eclipse molts, where they molt into off-season dull plumage and look like hens. But I've never heard of eclipse molts in Orpingtons.
The second thought I had was hen feathering...
I would keep her in a dust-free environment separate from the others and make sure she has access to proper food and water. I would expect her to be fine, but you never know what disease she might carry. Watery eyes are pretty common and can be a sign of many underlying conditions, but as long...