I am beginning to suspect my chick starter feed might have killed 2 of my chicks. Both had an enlarged swollen area on their upper breast when they died. Their last few hours they were lethargic and did not want to eat, drink or move. I tried dipping their beaks in egg yolks and sugar water but still lost them. The chicks are just one week old now. The starter we are using has split peas that seem large to me but I am new to this. When I go to refill their feeders each morning, the chicks have eaten up all the feed except the peas. Is it possible that my 2 dead chicks were victim of a feed size too large? I had not been providing grit as I assumed the starter was safe. I have begun adding grit this afternoon as soon as the deaths occurred. All other chicks are healthy and happy. Any thoughts or suggestions would be appreciated, thank you!