Dan, I think it all depends on the size of the bluegills. My initial thought is that you are bass heavy and need to be thinning instead of stocking. On the other hand, if you stock 6 inch+ CNBG, it might be OK. Here's my ideas. By the time the water/weather cools enough to safely transport and stock fish, spawning time will be over. However, you have a good chance of getting a better deal on larger fish at this time of the year. The Farms may not want to carry them over. Next spring the price of larger stockers will be up, if you can even get them.
