Reys, restaurant review: This posh chicken shop is the long-awaited new concept from Pizza Express

Corn Exchange Street, Cambridge, CB2 3QF (01223 322 399)

A derelict pub has been fitted out in bright, clean sort-of-Scandi style

Posh fried-chicken shops and rotisserie joints are springing up all over town. Forget KFC and Nando's: at this rate there'll soon be only one possible answer to the question, "Why did the chicken cross the road?" – to be brined, marinated in buttermilk, deep-fried and served on a waffle.

So why have I made the trip to Cambridge for lunch in this particular posh chicken shop? Ah, well, Reys isn't just a restaurant. It's a pilot, a proto-chain, the egg from which a chicken-themed dynasty will eventually hatch, gobbling up prime sites in malls across the land. It may look like an independent, with its quirky trappings and chalked-up quote of the day ("I believe in a wing called love"). But Reys is the long-awaited new concept from Pizza Express, now owned by a Chinese private equity company. It's the chain's first non-dough-based offering in 50 years, though to imagine dough is not the driving force would be misguided.

Cambridge was presumably chosen for the trial launch because the city centre has already been colonised by every other mid-market chain. A derelict pub has been fitted out in bright, clean sort-of-Scandi style. Behind the open kitchen, ranks of chickens rotate soundlessly and smell-lessly on spits. There's a fox motif: fox and chicken decals on the walls, and chairs dip-dyed in brush-like orange and white, to tie in with the name, a play on "renard", the French for fox.

It's an odd choice of theme. Not only can you not imagine anyone, ever, saying they fancy a "cheeky Reys", but it seems tactless to introduce the idea of a poultry-predator to diners who are about to sit down and eat chicken. But then there's a lot that's puzzling about Reys, given how intensively every aspect of it must have been researched.

According to their own creation myth, it's the product of a chicken-crazy team who fell in love with the French way of roasting birds, experimented with a garden firepit, and are now showcasing the results along with a range of bespoke sauces and sides. In truth, the food offer has been created – or should that be synthesised – by the ex-development chef of Waitrose and Morrisons.

His menu eschews the "do one thing and do it well" approach, to enter territory which can only be called "all over the place". Unlike Soho House's Chicken Shop group, which offers just rotisserie chicken and a handful of sides (at slightly lower prices), Reys' menu is a smash-and-grab of deep-fried wings, nasty open sandwiches, pulled-chicken buns and some Asian-inflected sides.

It's hard to mess up avocado on toast, but they do it here: slices of cold, under-ripe fruit dressed with lemon and a shaving of red chili, on what seems to be a giant two-day-old crouton. An insistently sweet barbecue sauce haunts the meal like a recurring nightmare. Deep-fried wings – disagreeable mouthfuls of fat, bone and batter –rapidly surrender their crispness to this one-note salsa; it masks any other flavour in a pulled chicken bun, and is slathered over – the horror – deep-fried battered sprouts, a dish which prompts my friend to hiss "who ordered the testicles?".

But Reys will stand and fall by the quality of its chicken – corn-fed, welfare-assured birds available by the quarter (£6.50) or half (£11.50). And the chicken is easily the best thing about our meal: no tricks – simply rubbed, roasted and rested, leaving the meat tender and full-flavoured, the skin crisp. Gravy, too, is the real deal, and there's a decent Asian slaw, banging with nam pla, coriander and Thai basil, though you could argue that these items don't belong on the same menu, let alone plate.

The kitchen's compulsion to hide everything – even desserts – under fresh herbs comes over as a cheap attempt to make the food seem more interesting than it actually is. It's the garnish equivalent of the beards and flat caps on the staff, or the display of faux-hipster Etsy-bilia, including a framed cleaver we could usefully have deployed on the avo on toast.

Given that Reys has been carefully incubated for maximum roll-out potential, the effect is oddly incoherent. If they'd stuck to doing rotisserie chicken brilliantly, with a few solid sides, I could see it succeeding as a modern, slightly more upmarket rival to Nando's. But they've tried to borrow from too many sources and ended up with something that references dining trends without turning them into something original.

That fox theme could come back to haunt the well-feathered backers of this pilot project. If it works, they'll be seen as guileful predators, sinking their teeth into their quarry and making off with the spoils. And if it doesn't, they'll be roadkill.

Food ***
Ambience ***
Service ***

Reys, Corn Exchange Street, Cambridge, CB2 3QF (01223 322 399). Around £20 a head for three courses before wine and service