Make a realistic assessment of the possible damage. Submit carcasses to the Department of Primary industry and Fisheries or the Parks and Wildlife Service for examination. Eagles are easily scared off by humans. If possible, move stock closer to people. Goats especially benefit from this and provide some shelter for their kids.
Scarecrows can work well if backed up by shooting to scare.
If you do this, please remember, you must have a permit from the Parks and Wildlife Service, so you cannot be accused of shooting at the birds. Notify the Parks and Wildlife Service. We can help. However, in several decades of managing this problem we have only had to capture a few eagles. Keep poultry near habitation and provide shelter.