Place chicken in a heavy 5 quart stockpot with water to cover.
Add the onion, carrot, celery, bay, peppercorns, salt, thyme and rosemary.
Bring to a boil, reduce and simmer for 1 1/2 hours.
Skim scum if needed.
Remove chicken and set aside to cool.
Remove meat and return bones to pot.
Simmer for 1 hour more.
Strain well and remove any fat you can.
Dumplings------------------.
Combine flour, soda, salt.
Cut in shortening until flour resembles coarse crumbs.
Add the stock, buttermilk and thyme.
Stir to make a stiff dough-and it will be stiff.
Turn out onto a floured board and knead gently 6 times.
Wrap in plastic and chill 1 hour.
Bring strained broth to a boil, reduce to a simmer.
Roll out the chilled dough to 1/8 inch thick, and cut into 4x1 inch pieces.
Drop them into simmering stock and stir gently.
Cook for 10 minutes, add the chicken and cook for 5 min more.
Season with salt and lots of pepper.