Greg pretty much summed it up. Charles Alsheimer wrote that with too many does the bucks would spend an overly amount of time breeding when they should have gotten back to eating before the harsh weather sets in, thusly adding to their weakened state and adversely affecting their chances of survival. He also suggested there was no real "second rut" but that actually what was happening was with so many does the bucks aren't able to service all of them and the ones that don't get breed in the rut go into a dormant stage and come into heat later in the season, therefore later breeding by bucks instead of foraging. NCYankee also has a good post and something that could be missed. I always thought taking a large older doe was the best but saw a show that was indicating younger does should be taken to reduce herds as the older does would be drying up and less productive in their olde years as opposed to a younger doe which would have more years ahead for production.