Hi All. Somehow I have some chickens with bright yellow poo. It's runny. They are lethargic. It's not impacting all of them but I have three that were just fine a couple of days ago. I was doing some research on here and came to the conclusion I am dealing with blackhead. I have (had) a very healthy flock...this has just cropped up in the past two days. Should I stick with the Acidified copper sulfate mixed with vinegar in their water or should I pull out the heavy hitter, Valbazen. Also, I could use some advice on some young chicks. These chicks are almost a month old. Can they receive the same wormer? Really perplexed about this, as all was well with the flock until recently. Thanks in advance for any help.