~They shouldn't brumate. A little cooling is debatable, but real brumation is asking for trouble.
i.e. - Death
Many folks lately have said tht they think Boas breed despite cooling, and not because of it. I tend to lean toward that side of the argument a little.
I think a little bit lower temperature at night is sufficient to prompt them into action, but I am not experienced at breeding boas, just colubrids, although I have a gravid girl or two, or three right now myself.
Day time High, Night Time Low fluctuations are a fairly tried and true method, but if they are going for it, they are going for it.
How big (weight) is your female, and how old?
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Jeremy J. Anderson
snakepimp.com
gemstatereptiles.com
Of course it's my opinion, I said it, didn't I?