Chickens losing weight and drop of blood on dropping board

[cheepcheepnash]

Do you have any suggestions if I found a bit of blood in Sweet PDZ on the roosting dropping board? Should I treat for cocci?

I have several chickens who just started laying this week for the first time. When cleaning their coop today, I noticed a 1/2 dime-sized red sweet PDZ on their dropping board.

Four of them were treated for cocci when they were chicks. 3 of them had never been treated. They finished an antibiotic for a respiratory infection one week ago and I've been giving them probiotics in their water this week. They seem normal in terms of activity level and their vents all look fine. They have lost weight from last week. Most have lost 4 ounces or so.

Could this be normal in new layers? What would you recommend?

 

[Wyorp Rock]

If possible get some photos of what you see.

Was the blood in poop or fresh blood like it could have dripped from a broken toenail?

If all are acting normal/eating/drinking, etc. then I would monitor them for a day or two. Take note of droppings and look them over for any injury as well.