Hello, new to the this website but decided to join as we lost all 19 of our 4 and a half week old chicks a couple days ago. We did everything right, kept them in two different big steel tubs, we used pine chips, had brinsea hot plates, constantly changed their water and made sure it was clean and warm, constantly cleaned out their food and made sure it was full we even kept the birds in the big galvanized tubs that you see in tractor supply in the house so we knew we could control their heat better, we kept a thermometer in their as well. They were growing great and were almost fully feathered. Then we fed them one night and 15 minutes later they all started to die and within 3 minutes of eachother they were almost all gone, it was awful. It started when I heard flapping from one and checked the tubs and it was laying face first seemingly dying/dead. grabbed it and it was and we were utterly shocked. then we noticed another was having a seizure and slumped over and then went belly up and as we started to look at all of them we noticed they were all breathing heavy and slumping and flapping and going belly up and then 3 minutes later we were left with only one of them as my wife was screaming and crying because we felt so helpless. The one left mustve ate last and seemed ok but sure enough a couple minutes later heavy breathing slumping and then flapping and seizing and then dying. We have submitted 2 of the birds for necropsy and we are testing the food. We checked DuMor chick starter online and and noticed there was a recall for too much calcium between december and february however ours was made in march but it was the exact same brand number from the recall. So we don't know exactly what happened yet but it has to be poisoning right? I've never seen such a mass death before in chickens and so close within eachother and 15-20 minutes directly after feeding them more of their food. Please let me know what you guys think, as I NEVER wan't to experience this type of thing again it was terrible watching these birds we had grown to love go one after another after another so quickly.