If they are friends, it will be hard for you to boot them off. I think you should give them the ultimatum of doing their share of the work or they won't hunt next year. In the mean time, maybe you can come up with a few excuses of your own to limit thier time in the woods this year. Something else to consider is this, how much was your time in the offseason worth? Let your friends hunt and they can be responsible for most or all of the costs for the year. Let them pay for feed, fuel, meat processing, maybe even a shoulder mount, etc. Hit em in the pocetbook and they may want to get off thier butts next year.