Even in the midst of fantastic (or historical, or science-fictional) adventures, your characters are going to have to stop sometimes for a bite to eat.
The late Diana Wynne Jones, in her Tough Guide to Fantasyland, speaks eloquently of the Stew that appears to be the only menu item available in so many of the realm’s inns and taverns. There’s a certain logic to the idea — if you’re going to be serving hot food at all hours of the day in pre-industrial conditions, a pot of something that can be kept at a low simmer over a slow fire makes a certain amount of sense. So does going in the opposite direction, with things that can be deep-fried or stir-fried in a hurry when they’re ordered, but it’s not often that you get a party of hungry treasure-seekers settling down at the local tavern for a plate of assorted fried stuff.
(Not chicken, though. Time was, when any chicken that made it to the dining table was likely to be a stewing hen, retired from the egg-producing game because of age and likely to be tough as an old boot unless given the slow-simmer Stew treatment. Fried chicken was a luxury, since it required the sacrifice of a young hen still in her egg-producing years. It’s only in the decades since the middle of the twentieth century that chicken has become cheap and mass-produced.)
But if your characters are going to sit down to a good bowl of Stew, take at least a minute or two to consider exactly what makes that particular stew different from another stew in another place and season.
If it’s a meat stew, what kind of meat is it? Beef, from a superannuated dairy cow? Beef, from cattle raised for meat? Was it purchased from a butcher shop — are they in a town that has a butcher shop, then? — or was the animal raised by the innkeeper and then slaughtered? Or are your characters travelling through wool-producing country, where the common meat is likely to be mutton or lamb? Or are they on the edge of the wilderness, where wild game is the commonest meat?
Are your characters traveling through a dairying region, where butter is the common cooking fat? Or are they in olive oil country? Or do the local cooks use chicken fat, or lard?
And what time of year is it? Is it winter? Before canning (a 19th-century innovation) and before reliable refrigeration (the 20th century), there were no out-of-season vegetables to put into those stews. Wintertime meals would feature the kind of root vegetables that could be kept in cool dark places until spring — turnips, hard squashes, yellow onions, potatoes — or vegetables that could be dried or salted or pickled (sauerkraut, kim chee, parched corn, dried beans.) Fresh greens wouldn’t show up again until the coming of spring.
Research — here I am, beating that drum again! — can help you keep your travelers’ tavern meals from becoming bland and generic.
Dr. Doyle's Blog 
I thought your standard frying chickens were immature cockerels, because having more than one rooster in a small flock was trouble, and you had to do SOMETHING with the excess boy chickens? Of course, this is based on a memory of Laura Ingalls Wilder describing what’s going to happen over the next couple of years with the flock of just-hatched chicks that Mrs. Boast has given her family to thank them for their hospitality during a snowstorm.
I’ve always thought it would be fun to have characters in a tavern complaining about dodgy rissoles the way that Marcus Didius Falco does in Lindsay Davis’ novels.
I amuse myself all too much with food… like looking up “what sort of fish would have been common in a nearby pond that the landlady’s son probably shouldn’t have been poaching out of?”
Surplus cockerels would be another source of frying chickens, you’re right–much as male calves in a dairying region are likely to become either oxen or veal.
I keep explaining that last bit to people who wonder why veal and veal stock seem to be the defaults in classic French cuisine.