Hi!
Welcome to BYC! Best of luck with your flock. BTW, I feed my chickens Purina Layer too. I start them a little later than you did because I use Medicated starter until they are about ready to lay. I don't know if that's right, just the advice I got from my farm store when I bought my first chicks 4 years ago. I haven't had a reason to question it. 
Welcome to BYC! Best of luck with your flock. BTW, I feed my chickens Purina Layer too. I start them a little later than you did because I use Medicated starter until they are about ready to lay. I don't know if that's right, just the advice I got from my farm store when I bought my first chicks 4 years ago. I haven't had a reason to question it. 



Don't beat yourself up about it! Just read, read, read. AND ask yourself questions about the information you are given. Like: Does what I just read make sense? Do research. Everyone learns every day if you are inquisitive.