I've used some of the Knorr chicken product. Better than the pallid canned/boxed stocks I can get around here. Salty, as expected for such products. Not as good, of course, as a well made stock, but an improvement over the cans and boxes and certainly easier to store. Chicken powder and chicken fat.
You might want to try More Than Gourmet glaces and demi-glaces. 1.5 ounce cups. Available on Amazon. They are true reduced stock. Available in chicken, veal and beef, lamb, fruits de mer, turkey, etc.
"Kitchen duty is awarded only to those of manifest excellence..." - The Master, Dogen