Since the hike in energy prices, I've started using my slow-cookers more regularly again. I have a small one for soups and stews (unless I want to bore myself with vegetable stew every day) and a large oval shaped one capable of holding a large chicken. Each of them cost me a quid from car boot sales.
I've experimented with cooking a chicken in the larger one in two ways. The second way has more potential. It involves spatchcocking (cutting out backbone) the chicken first, but putting into the cooker in its ordinary shape, with breast uppermost. I season the top with paprika and garlic granules. Then I heat it for an hour on 'high' for an hour, then turn down to 'warm' and then bugger off (seven to eight hours usually. If I turn it down to merely 'low' this overcooks it over eight hours, so 'warm' does nicely).
On returning, I remove from pot, open it out and place on a metal tray and stick it under a lowish grill for 15 mins or so. This produces a chicken with a fair approximation of having been roasted in an oven, without having to stand guard over it and baste it, and probably burning myself. Of course, some people may have wonderful cookers that have timers they can set, and a variety of temperatures that can be scheduled for various times. I however am a lowly soul with humble devices.