Thank you. I am feeding medicated food and have probiotics and electrolytes in the water. Hoping not to lose anymore.Sometimes they just die. Here is another reason...
Coccidiosis is caused by a protozoa, and is the most likely cause of death for young birds, especially around 3-6 weeks old. The protozoa live in the intestines of almost all birds, but gradual exposure builds up their immunity. Infection is common around 3 weeks old because it has built up in the brooder faster than the bird’s immunity. There are however several different species, so when you bring birds from different sources together, they can cross infect each other with strains they are not immune to. Infections can also happen because of poor cleanliness, or if the chicken’s immune system is suppressed by stress.
Not fun time for you sorry to hear about your loss. I would try medicated food and add probiotics to the water. Someone with more knowledge may be able to help you better. This is my best guess.