Help - what size of slow cooker to roast a chicken

[Sunshine511]

Just as the title suggests, I want to buy a slow cooker big enough to roast a chicken. Does anyone know what capacity of slow cooker I need? Thanks :)

mine is 3.5 litres and i can fit a chicken in that. some people rave about using theirs for this - i've done it twice and it was disgusting both times - hard and dry on the outside and bairly cooked on the inside. my cooker is fab for everything else but not chickens whole