So, I have two bags of feed. The first one I got as just chick starter and it's manufacture date is 6/10/16 so it hasn't been sitting on the store shelf for very long. However I saw another chicken feed that has 20% protein and got that one instead because more protein for little baby chicks. However the manufacture date was 6/3/16 Since I started feeding that feed my chicks have started sneezing. Could this new feed be old and bad? I smelled it and it does smell 'less' potent than the other food I was feeding before but I don't know if it is the difference between the brands or the medicated vs unmeddicated. Should I throw the new bag out since it's been on the store shelf so long?