A nice flock is kept in a walk-through exhibit with red and eastern grey kangaroos. They also have access to part one of Pairi Daiza's lakes for swimming, but during my visit they were on the visitor road.
Seen as no breeding has occurred whatsoever in all these years, I'd actually call this flock too small instead of a nice flock even though it does look nice from a visitors point of view.
@KevinB Walkthrough shouldn't be a problem, given the rest of the space. Their previously free-roaming pelicans bred after all, even though they did spent a lot of time on the paths. The kangaroo's might be a problem, as they do indeed not have a seperate piece of land (another husbandry flaw of the exhibit). However the recommended minimum group size is 10 animals, and I think they have like 5 or 6 of them. Group size is one of the most important factors in determining breeding succes in species like pelicans and flamingos, which I also suspect to be the reason why their cuban flamingo flock doesn't breed.
That is by the way in many parks a problem, in the Benelux alone I know Blanckendaell, Best, and previously Antwerpen and Planckendael whom had too small groups for breeding.