Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations Crappies, cull or not to cull

We have a nice 7 acre lake in Charlotte, NC that is well stocked with Bgill, cats, LMBass, a variety of pan fish and crappie. I read in another posting that in lakes smaller than 20 acres you should cull all crappies. If that is your recommendation I'll accept it, but can you give me some of the reasons why?
Also, could we add crawfish in the spring?

Thanks