Yet another dog attack - so sad and so mad. Good advice above (electrolytes for shock as noted - do this promptly).
Please also take some photos of the horror - it will be important later in taking action about the irresponsible dog owners, on behalf of your birds that were terrorized, maimed, killed.
If someone can get you some Rescue Remedy (Bach flower remedy) a couple drops in their water, freshened regularly, may help have a calming effect.
The survivors will probably be in a lot of pain and would benefit from pain relief (1 baby aspirin [81mg] crushed per cup of drinking water, changed out at least once daily). If anyone is bleeding a lot or you suspect internal bleeding don't do this or they could bleed worse. A vet can also prescribe pain reliever that doesn't have this concern, possibly Metacam.
JJ