The boarding schedule will display a lime green color for two scenarios.
1 - After deadline pickup: This is a setting in File, System Options, Boarding tab, Board Settings tab, Miscellaneous Settings tab.
For example, maybe your cut off for early checkout fee is a 12pm pickup time. You can enable this option so that appointments that checkout after your 12pm cut off time are flagged on the schedule and show in lime green.
2 - Exercise checkout: Kennel Connection has a feature so you can check pets in and out for their exercise. Then you can print Reports, Boarding, Exercise Timings to get the exact times pets are exercised for.
Right click on the appointment and click Exercise Checkout when the pet is to be exercised. Right click on the appointment and click Exercise Checkin when the pet is finished exercising. When the appointment is set for Exercise Checkout, it will show the lime green color.