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1000 keywords in an ad group probably is not the best way to run an ad though. Chances are you will have it shut down soon due to the under 1% CTR rule. I could be wrong though, but I highly doubt that 1000 keywords would be the most effective way to get the best CTR.
Your better off breaking them down into smaller groups with more targeted ads. This will do two things for you. First, your response will be much better and second, if something were to happen to one of the ads wheather shut down due to low CTR or disapproved, you don't lose all of your advertising power in one blow.