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Had you checked some of the hen's eggs by cracking them open to ensure they were fertile prior to setting other eggs from the same hen?
Prior to putting eggs in my incubator I have some for breakfast. That is the best way to be sure how fertile they are. At 10 days you should see some veining. Maybe either the male or female isn't fertile. I had a male I desperately wanted chicks from. None of the eggs from his females hatched. I put another nice male in with those females and had a very successful hatch.
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