When I was "re-batchelorized" the first time I wasn't really cooking yet, and that was when I first encountered the supermarket rotisserie bird (or maybe they had just been invented). This was 1968, and they were $1.25 each … and my answer to your question at that time would have been "ONE!" Even when I'd intended to save some, this fog of deliciousness would descend, and when it lifted I'd be greasy, grinning and cleaning up the pile of bones.
Under the regime of the latest (and final!) Mrs. O, we would get at least two meals from a decent-sized bird, no matter how prepared, plus a packet of the cooked and uncooked bones etcetera added to the freezer. After two or three of those had accumulated their contents and some appropriate vegetables would go into the crockpot, which Mrs. O referred to as the Shrine to Our Lady of Perpetual Broth, our night would be fragrant, and in the morning the results would be strained through layers of cheesecloth. That would be good for at least two more meals, whether soup, gravy, or chicken and dumplings or noodles.
Now Mrs. O eats no birds (nor beasts), so the only time I cook a chicken is when she's away for several days or longer. Next month she'll be gone 2 1/2 weeks … so I'll get back to you on this!