I would still treat with Corid.Today, I noticed that her crop is swollen I touched it gently and I noticed that her crop is empty of food even though I saw her eat but it is full of water. Should I treat her for cocci nonetheless or is it some other disease ? I'm confused.
What are you feeding?
Does she have a source of grit (crushed granite)?
Keep watch on her to see if the crop goes down. Depending on how you are brooding her, it can be hard to tell. Chicks that have light (heat lamp) 24/7 will eat and drink all hours of the day, so monitoring the function of the crop is harder to do. If you are using something like a heating pad for brooding and they have a natural sleep cycle (up when light/go to sleep when dark) check the crop before she goes to sleep at night, then first thing in the morning - should be full at night-empty in the morning.
Let us know how she is doing.