Before my girls turned 18 weeks old, I started changing their feed from Start& Grow to Layena. I mixed batches. 1part Layena, 3 parts Start&Grow, then 2 parts each, then 3 parts Layena to 1 part S&G, then then all S&G. Each mixture was given for 2 days.
Basically they are giving you their GARBAGE. Your chickens should get a nutritionally complete chicken feed every day as scraps do not meet the nutritional requirements. How many chickens do you have that requires 50 lb of feed every month? If you can't afford to feed them properly chicken feed...