Milly is making feather boas for her dance team. Each flamingo has 20 tail feathers, and it's only safe to pluck 25% of their tail feathers at one time. If Milly needs to make 12 boas, and each boa has 200 feathers, how many flamingoes does she need to harvest?
Please reason step by step, and put your final answer within \boxed{}.
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