The bigger question here might be the total feed. 100 pounds of regular feed, plus 50 pounds of scratch in 30+ days for 11 chickens?
That, my friend, is far more the issue, not so much the percentage of scratch to feed. If your friend went through 150 pounds of feed in 30-35 days for 11 chickens, that is almost 3 pounds of feed, per chicken, per day. You've got major, major loss to wild birds, rodents, etc and/or you have tremendous waste, or both!!!
No way 11 chickens can justifiably consume 3 pounds of feed per day. Not two pounds per day. Not even a pound per day, not hens. Sorry. Sounds like you and your friend need to keep good records, review your feeding practices and come to common agreement. Even in cold weather, when I feed the most, and have zero ranging because of winter, does my feeding approach 1/2 pound of feed, per day, per hen. Time for some calm, number crunching with your friend and a coming to the meeting of the minds.