In a large pot over medium heat, combine chicken, water, onions, celery, salt, nutmeg and pepper. Bring to the boil, then reduce heat and simmer 2 hours, adding water as needed, until chicken is very tender. Remove the chicken from the soup. Refrigerate chicken and soup.
When fat solidifies on surface of soup, remove from refrigerator and remove fat. Remaining soup should equal about 2 1/2 litres.
Remove sweetcorn from cobs by splitting kernels lengthways with a sharp knife and scraping sweetcorn from cob. Combine soup and sweetcorn in a large pot over medium heat and bring to the boil. Reduce heat and simmer until sweetcorn is tender, 10 to 15 minutes.
Meanwhile, place two of the eggs in a small saucepan and cover with cold water. Bring to the boil and immediately remove from heat. Cover and let eggs stand in hot water for 10 to 12 minutes. Remove from hot water, cool, peel and chop. Set aside.
Chop cooled chicken meat and add to soup.
In a medium bowl, beat remaining egg until light in colour. Beat in flour and milk until smooth. Drop batter by partial spoonfuls into hot stock to make small (1.25cm) dumplings. Cook, stirring constantly, for 2 to 5 minutes, until dumplings hold their shape and float to the surface. Stir in reserved cooked egg.