You asked whether Connecticut law requires a dog to be put to sleep after biting someone three times.

Connecticut law does not require that a dog that has bitten someone three times be put to sleep. If a dog is off the owner's property and bites someone, the dog must be quarantined. If the bite occurs on the owner's property, the dog may be quarantined. Any dog that has been quarantined may be "restrained or disposed of. " The owner must be provided with notice of the decision and have the ability to appeal (CGS § 22-358(c)).

JKM: eh