2nd Post - what is wrong with my hens?

I posted a few weeks ago and got no replies. Am hoping someone might be able to tell me what is wrong with my chickens.

Symptom: Finding blood-tinged fluid soaking through several layers of paper towels and newspapers every morning in the coop.

This started several weeks ago; I wasn't absolutely sure which hen it was coming from so I took two of my three hens into the vet. She could find nothing wrong with the Light Brahma, diagnosed the Buff Orpington with metritis. A fecal sample tested negative for worms. We did a week-long course of Baytril (antibiotic) and an anti-inflammatory. I did not notice significant improvement.

We had to leave town and apparently the situation worsened to the point that the housesitter noticed the chicken's droppings around the yard were also blood-tinged. She took the same two hens back to the vet. This time, the vet decided the second hen was also affected, and diagnosed them with cecal worms. When I spoked with the vet by phone she explained that the diagnosis can only be confirmed post-mortem but she seemed to think that was the cause of the problem. All three hens were given medication to be repeated in two weeks.

We are a week past the first round of medication and I am still finding copious amounts of blood-tinged fluid in the coop in the mornings, although I haven't noticed it in the droppings during the day. Should I expect to be finding this until after the second round of medication? Or is it possible that something else is wrong with my birds?

For the record, all three are perky, normal behavior and appetite. The Buff Orpington does have a bit of prolapse but not too bad. The vet was happy with their weight and appearance. The third hen, an EE, has not been examined. It's possible (but I can't prove it) that she isn't affected by whatever is going on, although, of course, if it's worms, it's good that she's being treated, as well. Thanks to anyone who can help.

Here's a picture I took of the girls yesterday:

 

Thank you so much for this input.

I was out of town when the first round of medication was administered but whatever they were given, yes, it was put on bread to feed to them. The second round of medication is supposed to be given two weeks later, which will be next week. I just wasn't sure if I should still be seeing significant symptoms after the first round of meds. I have a call in to the vet but haven't heard back yet.

They are acting way too healthy for coccidiosis and they are 15 months old so that possibility never occurred to me. I hope it's not that! At no point has any one of them appeared or behaved under the weather - it's just all this blood-tinged fluid that I'm finding in the coop. It's been going on for close to a month at this point - wouldn't they all be dead by now if it was cocci?

They eat laying crumble. Their primary treats are BOSS and small amounts of scratch. We give them carrot tops when we have them and my husband has been giving them handfuls of cereal when they wander into the kitchen (which is getting to be often, now that they associate it with treats!)

We store their food in a closed room of the house - no rodents.