50' trees on three sides of my yard cause the rollers to bank three or four times before landing. Coopers always strike when they get down to about 20'. My homers would exit the flock and home in separately bombing through the bobs. They were also stronger and faster fliers than the rollers. My rollers were Turner/Marino crosses and were fast and deep but rather infrequent when I first got them. First year breeding produced a hen who was very frequent and not so deep. She really improved my birds, and then the slaughter started about 4 years into my breeding program.