Aaah, so there's the connection! More rabbits will be followed by more predators. More predators necessitate more roosters to protect the chicken flock.
That may be true, or it may be just a coincidence. This year I've let my broody hens hatch out chicks each time they want to set, and there are less pullets in the For Sale pen than cockerels in the For Dinner pen. And there seems to be more than the usual number of rabbits in my yard, both...