It is best to keep all golds together, even having a few Jumbo Browns (if you are wanting bigger birds) or pharaohs. My reasoning is, some are going to be carrying more lethal genes than other and as the browns, lots of little color differences come out. If you look at browns, they aren't all the same, there are little tidbits that make one different than the others. Unless you see a totally off color that you want to strive to produce, my highest recommendation is keeping the golds together. I started to do this for 1. less DIS (dead in shell...lethal genes) and 2. more variations in gold.