I have 9 one month old Serama chicks. How long should i feed them chick starter for? They are not very big my birds. I find the grower is big pieces still. I also have a second question I have 4 six month old silkie pulleys, one started laying, but I have been feeding them grower food with crushed oyster shells on the food. Should I keep doing that, or should I switch them to layer food? Thanks!!