Does cooking raw meat/poulty extend its shelf life? I pulled a chicken out of the freezer a couple of days ago with the intention of making stock/soup. It's defrosted now and ready to go, but I don't have the mirepoix ingredients and I'm too lazy to go to the store for just that. Since it's just now defrosted, I've got a few days, right?  What if I'm still too lazy to go to the store three days from now, so I roast the chicken close to its maximum expected "still fresh" time and then refrigerate the cooked chicken? Would that effectively "restart the clock"? Lets say I hold on to the cooked chicken for three days before finally getting around to making the stock. Would it be right to expect that stock to have the same shelf life as it would have had if I had made the stock with the freshly defrosted chicken? 

For the sake of this question, assume that the chicken was frozen immediately upon purchase, defrosted in the refrigerator, roasted to an internal temperature of at least 165F, rested, then promptly refrigerated.

I could ask the same of a beef stew. Can I cook the meat to give me more time before I put together the stew?

In both of these cases I'd expect a certain quality loss, so I am more concerned about safety than optimum flavor or texture.
Shelf life for flavor...or for safety?  Two different issues.  Many variables.  How was it handled before freezing?  How was it defrosted?  How is it being stored after defrosting.  Those will all be factors impacting the safety issue. 

Lets say to minimize the safety concerns you roast upon safe defrosting.  Now you have a safe product (from a bacteria standpoint), as long as you handle the chicken appropriately after cooking. Keep it out of the danger zone...even freeze it...it will be safe...but flavor probably begins to degrade over time (picks of fridge flavors...freezer burn if frozen).

Now you take that chicken and make stock.  You pull from fridge (or defrost appropriately) and cook to boiling while making stock.  That kills any bacteria that MIGHT be present (doubtful if you cooked well and handled appropriately after cooking)...so from a safety standpoint you are probably fine.  However, you probably have a stock that is not as flavorful as it could be because of the lengthy holding time.

In the end, I would say (nothing to back this up but my own experience) the final stock has the same shelf life as any stock, but it probably tastes different from one made with the freshest ingredients.