Hire outside help for as many tasks as you can afford. Then, see whom else you can talk into doing things you can't afford to buy. Hold a family summit emphasizing the need for fairness and cooperation. Kids will cooperate more than you imagine if you just explain to them what you expect and how it will benefit the entire family. Use a daily task chart to keep track.
Kids are sticklers for fairness.
Teach your children to take on tasks efficiently and empower them to do more. Hold a lottery for assigning chores. Include anyone age 4 and up. Redirect inappropriate behavior, but be sure to praise a job well done. Listen to the report to find out why.