I have a flock that is over a year old. This year I also got 5 babies that are eight weeks old now. I am starting to combine all the girls together but I am worried about the feed. Is it ok for the older girls to be eating the starter food and the babies to be eating the layers food? There is also oyster shell out that the older girls have access to at all times. Is this fine or should somehow try to separate the food? Thanks for your input.