Lethargic Rhode Island Red! Help!

[Dragonbot03]

Hi! First time posting here! My family has six backyard chickens, and one of the reds looks positively miserable! She's lethargic, only eating a bit, and her comb is pale and flopped over. She doesn't look injured, her backside is clear. The coop is connected to a fenced yard that is cleaned daily, and there are several heaters. They're given clean water and fresh food protected from the elements. They also have a diatomaceous earth bath. Any clue what's wrong with her? This is sudden, and none of the others look ill at all. They're all about 2 years old

Small edit: We've brought her inside the house and she's drinking water okay

 

[Eggcessive]

Is she being picked on by the others? It looks like that from her face and comb being scabby and black. Could she be kept away from water or food by the others? How does she crop feel? Full, empty, firm, or squishy? Can you see if she will eat some watery mushy chicken feed and some scrambled egg bits? What does her lower belly feel like? Does it seem fuller than normal? Is her poop normal? Does she normally lay eggs?