Concept:The illustrated management practice described is brooding, which is the care and warmth given to young chicks.Explanation:Brooding starts from day old and continues until the chicks can regulate their body temperature on their own.Chicks usually need this artificial warmth and protection for the first 6 weeks of life.At around 6 weeks, their feathers are developed enough to cope without a brooder.Thus, the correct duration is from day old to 6 weeks.Answer:C. 6 weeks