Surely a condensed chicken broth is nothing more than a reduced chicken broth? If home-made from a chicken carcass this could be flavoured, whilst cooking, with a peeled carrot cut into quarters, a peeled onion cut into quarters on the root and a finger of leek plus a bay leaf, a couple of peppercorns and a sliver of mace. For a brownish stock, brown the carcasse and vegetables in butter/oil prior to adding liquid - water and for a white stock just put everything straight into the pan. Cover all the vegetables and carcasse with water at a rate of 2-3 pints for 1 chicken carcasse - and cook at a simmering point, covered for 2 hours.
After 2 hours of cooking, strain all the mixture through a sieve into a bowl. Following this one can reduce the stock further to a syrupy consistency to use as a "jus" or gravy, or cool and freeze for further use in soups, stews, fricassées etc.
Season with salt and pepper at the end of cooking.
The same principle applies to meat bones from beef, lamb, venison, pork or wild boar etc., cook, after browning or roasting, once water, vegetables and seasonings have been added for 4/5 hours. Do not add salt whilst making the stock as boiling/reduction increases the salt content.
A fish stock made from whole, small fish, fish heads, bones etc., should not be browned before any liquid or additional flavourings are added and should not be simmered for more than 25 minutes before being strained and then reduced by placing in a clean pan.
Hope this helps,
Archiduc