Lathargic and fluffed up chicken-second time.

[Daisies]

So my 3 year old golden sex link is sick again. The first time she stopped laying eggs and was a little lethargic but she had no problem eating and drinking. (I call her the pig) I had chicks so I started giving her medicated chick food (As often as I could but she still was having her normal food) watered down with olive oil, apple cider vinegar and Epson salt. I kept her on that even after she started laying eggs again... Probably took her a week to lay eggs and then I gave her the food for another week. Then I let her go back to her normal diet. It's been 3 weeks since then. She started eating her eggs and the shells were thin. I have oyster shells in the coop for them. I assume she had a protein deficiency. Her eggs just started having more normal shells. Still not quite like they were before. Then today she didn't lay an egg and started acting sick again like before. I don't have chick food now and I don't want this to happen again. Any ideas or other threads that I should look at?
Thanks for your help.

 

[Daisies]

Update! Well she was sitting in the corner and I went out to close up the chickens she was still there but she had laid a shellless egg and once I took it she went to eat. Looks like maybe she's fine after all.