My chicks are currently 7 weeks. They free range during the day. Judging from the amount of feed I have to add daily, I'm approximating that it's about 50% of their daily intake.(possibly less) I have them on a 20% grower (Dumor) and supplement water with poultry cell 2x a week. I planned on continuing this regimen and supplementing with oyster shell when they reach appropriate age. My thoughts are that the boosted feed and vitamins will fill any nutritional gaps that may occur from free ranging. Is this a valid concept? or am I over thinking?