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There are ton's of reasons why your snake could have stopped eating. If you can provide us with some basic information, (Temp's, Humidity, ect.) then we may be able to determine the reason.
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One thing I would look into is the temps. It sounds like it is a temp issue due to the fact that he was eating well for a while. This time of season it is still possible to have a snake go into a personal brumation because temps are to low. Let us know all the details about your husbandry before we can make any kind of conclusion.
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The reason why we need details, is put this case into reality. You go to the doctor and say you don't like a certain medication, yet you won't tell him what the medication is. How can he help you?
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Good Luck,
Ryan McCullough