My suggestion is to observe her for one more day before you embark on a treatment. Her behavior being "off" is a signal to observe and investigate. Jumping into a treatment before you have accumulated enough information to point you in a direction may be inadvisable. Quite often, we see a hen have an off day and bounce right back to being normal the next day. This has happened to me with my chickens more times than I can count.
The green poop, normally formed, could be merely green vegetation. I see this in my flock a lot. Green poop that is from a sick chicken is usually green bile chunks floating in a puddle of white, runny mucous.
Orange-red intestinal lining in no way indicates coccidiosis. It's not very likely your flock is having another bout of it so soon. They usually enjoy a period of resistance afterward. Treating with Corid too often risks setting up your chickens for a thiamine deficiency. That is something that can open a can of worms you would rather not have to deal with.
Your Silkie may be transitioning from brooding the chicks to getting back her normal life. Her hormones are dwindling, and that may have an effect on her behavior. Think how "off" a woman feels after giving birth and nursing, then having that halt. Hormones can really take a toll, both coming and going.
If this hen is getting sick, you will see more definite signs in the morning and by noon tomorrow, you will have a good handle on whether she's sick or not. Also, take this opportunity to check her crop in the morning so you can rule that out.
