The mixed color on the Run Glance does not indicate there are different family pets staying in the same run. The mixed color is for pets arriving and departing at different times. So, if a pet is arriving and another is departing; if a pet is arriving and another pet is already in the run; if a pet is departing and another is staying.
In our example below:
On 10/16 - Roxie is departing while Molly is arriving
On 10/18 - Gigi is arriving while Lenny is staying in the run
On 10/20 - Lenny is departing while Gigi is staying in the run.
On 10/16 - Juju is arriving and departing for a one day stay while Coco is arriving.