I can easily get 4 meals for 5 from a chicken, but I don't serve a roast. I cook the bird and then strip the meat from the bones.
Typically I would make:
risotto/savoury rice/stirfry/easy thai spiced noodles with 1 breast
pasta bake/creamy chicken and veg jackets with 1 leg.
chicken and veg with dumplings/chicken and veg pie with the other leg
chicken tortilla bake/shredded barbecue chicken rolls or similar with the other breast.
Then I would make stock for soup and add all the little scraps from the wings and underside of the bird along with carrots, onions, leek and either barley or rice. Soup would typically last 2 lunches.
So, in effect, I would get 6 meals for 5 from a chicken. It's not everyone that would want to do this, though.
Other meats get the same treatment in here. I don't buy a lot of meat because I am veggie and can only stomach buying ethically reared (outdoor, organic/wild) stuff for the rest of the family and it's really expensive.
I cook a pork joint and then divide it into enough for 3 or four meals, depending on the size. A lamb/mutton leg will get divided into 4 and then I'll make stock with the bones for soup. Same with the very, very odd beef joint that I buy. I make things like savoury rice/risotto, hedgehogs (rissole things made with potato and veg mash) barley mince, shredded barbecue meat rolls, pies/pasties, curries, fritters, toad-in-the-hole type things. A joint will give me the basis for meals for the family for most of the week.