I'm terribly sorry to hear of your struggles with your chicks! Because one batch was vaccinated and the other was not, we can rule out vaccine reaction. Also, since the chicks came from two different hatcheries, we can also rule out some disease from the hatchery. I have never had chicks or...
(1) Are you new to chickens / when did you first get chickens?
Pretty new - Got the first ones in April 2022.
(2) How many chickens do you have right now?
4 adult hens and 6 hatched in mid-May 2023.
(3) What breeds do you have?
Adult hens are BPR, BPR, Leghorn, and ISA Brown. Babies are...