I've never heard of it happening during breeding, but when cohabing you can get cases of canibalism. As far as her being defensive I would put him in there and just observe them for a couple minutes and if she's not having it then remove him. Also I've always heard you want to put the male into the females cage. Just my two cents. I'm sure someone with more experience will chime in soon. It is the middle of the work week after all

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