Lethargic Hen, but everything checks out as ok.

[Hawley2000]

I have a hen whos under 2 years old that is acting very lethargic! She hasnt laid in about 3 days, so I thought maybe egg bound since there is no nasal discharge and her face and eyes look good when they are open. Even though she is pooping pretty normal thats the only sensible thing I could think of. I gave her an epson salt soak and crushed a tums that she ate mixed with her food, nothing happened. So that evening I checked in her vent and I dont feel any egg or egg particals. She has an appetite when hand fed and even perks up and looks great when eating but then goes right back to acting lethargic within minutes!! Since having her inside Ive been feeding her a mixture of her layer feed, a cooked egg (with the shell) black sunflower seed, grubs and dried oregano. Her water is mixed with chicken vitamin powder and electrolytes. I should add, her crop is emptying and not impacted or sour mouth smelling at all. There is no lice or mites and I dont see any parasites in her poop. Any ideas on what is going on?!?