Earlier this spring I bought 15 chicks (different breeds) at my local TSC. Now they are getting older and it appears I might have 3 or 4 Roo's in the mix. If I'm raising them only for the eggs should I seperate the roo's from the hen's?
Well, that would give you a ratio of 4 roos to 11 hens, which is too high. Your hens will get no peace. They could get stressed out from all the male attention, stressed out hens don't lay well and are more prone to illness.
However, if you wanted to pick out one of those boys to keep, there would be no need to seperate him. There is no difference in fertile eggs vs. infertile eggs; not in taste, not in nutritional value, not even in looks - unless you know what to look for and look closely.
For 15 hens, it'd probably be best to just keep 1 rooster with them. You could get rid of the extra 2 (rehome, eat, etc.), or you could just give them their own roo coop. The general rule with roosters seems to be 1 rooster to every 10 hens.