Eggbound issues again - hen pooping yolk

[Chicken Lass]

Last year I had a hen that was eggbound and she died before I figured out what was wrong. I was giving my flock too much scratch feed and not enough calcium-rich feed. Now that I've been feeding them better, most of my chickens are back to laying eggs as usual and they all seem very healthy except for one. My ISA Brown Rosin is still having yellow yolk looking poop and isn't very active, spending most of her day standing or laying somewhere. I'm afraid she isn't feeling well at all and that she will end up like my other hen Sheila. Just very recently the back tip of her comb has turned white - not completely white, just faded. My chickens have gotten some occasional scratch, but not like they used to. They also had access to a kind of poultry block that has lots of different kinds of feed in it, though I took this back away not sure if I should allow any kind of other feed besides laying feed and oyster shell and grit.
Does anyone know what I could do for poor Rosin besides feeding her right? She hasn't gone back to normal apparently with the feed and I don't know what else to do with her. Is there some kind of antibiotic that could clean her out in case she has some kind of bacteria problem? It seems she's just pooping out yolk and that can't feel very great. She's still a good weight and has a halfway decent appetite - especially for cheese. Unless I can figure out how to cure her or at least get her to where she's not pooping yolk, I'm afraid she is just going to keep going downhill from here like Sheila did.

 

[<3<3 I <3 Chickens <3<3]

My chicken was pooping out yolk like that but she got over it. If you arn't already using it, I sugest you switch to organic chicken food. I heard origional yorgut helps!

 

[Chicken Lass]

Thanks! I've been giving all of them yogurt. I know I just said that Rosin has a good appetite, but today she didn't seem interested in even cheese. I also haven't noticed her pooping even the yellow stuff as much, so I hope she is not blocked. She did eat a little yogurt. I'm not sure whether she will get over it or not at this point. She seems pretty slow. What did you do for yours when she got like this? Also I don't know where to find organic feed (besides trying to grow it myself) - can it be ordered from somewhere? Thanks so much and I'll keep trying the yogurt.