9 week old pullet - yellow diarrhea and lethargy

[floralace]

I’m keeping chickens for the first time, and this is my first time dealing with a sick chicken so I’m a bit anxious. I have a 9-week-old Faverolles pullet that’s not wanting to get up and walk around, and is having yellow slimy diarrhea (pic below). Yesterday she was totally fine, and this morning she was slow leaving the coop in the morning but went out with my 4 other pullets - all of which seem fine right now. Then this afternoon I found her huddled in the corner of the coop, and I brought her into a quarantine pen. Any advice would be great, thanks

Gross poop pic below:

https://imgur.com/a/cvChitA

 

[A Man and his Chickens]

I found this on the site. I'm no expert but this seems like good info. Hopefully some more experienced will chime in.