Total daily consumption for 3 ducks: 3 ducks * 100 g/duck = 300 g.
Total weekly consumption: 300 g/day * 7 days/week = 2100 g.
Total consumption for 5 weeks: 2100 g/week * 5 weeks = 10500 g.
Convert to kilograms: 10500 g / 1000 g/kg = 10.5 kg.
Answer: 10.5 кг.