Evaluation is performed on any individual whose "evaluated" flag is false. So you could go through all of the population after breeding and set 'em all to false. That's ugly though. The right thing should have been for that feature to be in SimpleBreeder all along. I've committed a new version of SimpleBreeder which, in my delerious state, appears like it SHOULD work, but is utterly untested. I'm attaching it here. It's your job to test it. :-)