5 gallon nesting boxes

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I am starting a backyard flock of 6-7 Bantam hens (Black Frizzles, Blue Silkies & Black Mottleds) with 1 Blue Silkie Bantam rooster. I am making 3 nesting boxes from new 5 gallon plastic buckets. I am wondering how and if anybody else has thoughts on these? I like the fact that I can remove them easily with door brackets and power wash them. They will have lots of small ventilation holes and perches for entering. Also, what is the recommended distance off the coop floor for Bantam nesting boxes? As they will be enclosed in a covered 8 foot high run where they will be able to fly, am I wrong in assuming a reasonable distance off the floor won't be a problem? Thanks! Happy Easter.
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