HELP PLEASE! 3 week/old baby lethargic

[KJzCola]

I have five three week old female chicks. All have been super happy and healthy thus far. Up until the most recent batch of water I had been adding probiotics to help get their systems up and running well. I went to check on them just now and my largest lady, the one normally body slamming the others and getting first dibs on the food, is barely moving. She is either sitting or standing up straight with her wings held at her sides. She has her eyes closed for the most part but when I rouse her one will always shut first for a few seconds before the other one shuts. She is holding her beak gapped open a lot, and thick spit is bridging the top and bottom of the beak when she opens it. It looks mildly as if she has drooled, because the corners of her mouth are wet and around the beak. No pasty butt, I checked. And she doesn't seem to have the energy to run away from me like she normally would. She keeps walking toward an edge or corner so she can hide her face not to be bothered. I am very worried that there's something wrong with her, it's just very abnormal behavior. I can't see any wounds, no blood (she has yellow feathers) just a tiny bit of poo on some of her feathers.

Pleas and thank you for any help and advice!!!!! I don't want my baby to die!
The picture is not great but it's the best I could get.

 

[Eggcessive]

What is your brooder temperature? Could it be too hot, or thaat you don't have a cooler spot to get to? At 3 weeks they should be tolerating 75-80 F temps just fine. At this age coccidiosis is the most common illness, and it is treated best with Corid or amprollium, a cattle medicine that is put into the water. Symptoms of coccidiosis are lethargy, standing puffed up or hunched, diarrhea or blood in the stools, ruffled feathers, and a poor intake of food and later, water. Dosage of Corid is 2 tsp of the liquid, or 1.5 tsp of the powder, per galllon of water for 5-7 days, and treat al chickens.

 

[KJzCola]

What is your brooder temperature? Could it be too hot, or thaat you don't have a cooler spot to get to? At 3 weeks they should be tolerating 75-80 F temps just fine. At this age coccidiosis is the most common illness, and it is treated best with Corid or amprollium, a cattle medicine that is put into the water. Symptoms of coccidiosis are lethargy, standing puffed up or hunched, diarrhea or blood in the stools, ruffled feathers, and a poor intake of food and later, water. Dosage of Corid is 2 tsp of the liquid, or 1.5 tsp of the powder, per galllon of water for 5-7 days, and treat al chickens.

Thank you for your help. Everything I've read says to start the brooder at 95* the first week and decrease by 5* every week. Since they were hatched on a Monday, I agjust the temp in the brooder on Mondays. When I went to adjust this Monday is when I found her like that. The. Next time I went down (after decreasing the brooder temp) she already looked better, and by next day was almost back to normal WHEW!!!
I love my brooder set up because it provides a 10* range throught, so those a bit behind and those a bit ahead should all be able to be comfortable. But I guess this one was a bit further ahead she is the biggest so it makes sense. I went ahead and adjusted down again the next day, and they all seem perfectly happy with it so that's good

Thank you again for the help! This is my first batch of chickens and although I've read all about the signs of being overheated, to me it did not look like what was described. I failed to consider the temperature, but so thankful of the BYC community for always being there to help )