It would be beneficial to obtain a survey from each teacher. In the event that there are too many teachers to survey individually, a random sample for each district would provide information regarding satisfaction rating for each district. If it is broken down within the district by school, it would be necessary to ensure that each school has at least one response.
Also, it is important to focus on the actual questions asked on the survey. A surveyor wants to make sure that the survey targets the information they are seeking from the participant and that information will target the analysis necessary to make a good decision.