Place whole chicken in a large pot and cover with water. Bring to boil, then reduce heat and simmer for 1-1.5 hours until chicken is tender and falling off the bone.
Remove chicken from pot and set aside to cool. Reserve the chicken broth in the pot.
Once chicken is cool enough to handle, remove and discard skin and bones. Shred chicken meat into bite-sized pieces.
Prepare ribbles by mixing flour, egg, salt, and pepper in a bowl. Mix until it forms a crumbly dough. Add water if mixture is too dry.
Return shredded chicken to the pot with broth. Add butter, cubed potatoes, and corn.
Bring mixture to a boil, then reduce heat to simmer. Season with salt, pepper, and parsley.
Crumble ribble dough into small, irregular pieces and drop into the simmering chowder.
Simmer for 1 hour, stirring occasionally to prevent sticking.
Chop hard-boiled eggs and stir into chowder just before serving.
Taste and adjust seasoning as needed before serving hot.