Our chicks are about 5 to 6 days old i would say. We got the chick starter kit and a big bag of chick food. We put the heart light on them but there is no setting..We just guessed the distance. I'm not adding any of these things to water or food such as probiotics. Is it i they're chick food? They are doing great so far. They are happy and chirping. The temp seems to be good for them. I want to keep them healthy. Suggestions?