6-8 pounds: 2.5 to 3 hours
8-12 pounds: 3 to 4 hours
12-16 pounds: 4 to 5 hours
16-20 pounds: 5 to 6 hours
20-24 pounds: 6 to 6.5 hours
6-8 pounds: 2.5 to 3 hours
8-12 pounds: 3 to 4 hours
12-16 pounds: 4 to 5 hours
16-20 pounds: 5 to 6 hours
20-24 pounds: 6 to 6.5 hours