ACTIVE horses are those that you use in your everyday work or at least those that are on your farm. These horses will be taken into account for:
Besides, on an Active horse, you can record historical data (health records, competition, farrier, training, cost/expenses), while in Reference horses you just see a timeline of records in read-only mode.
On the other hand, REFERENCE horses are those that for any reason you are not monitoring and entering records.
Generally, these animals have some of these characteristics:
You can't create historical records on these Reference horses.
CRIO ONLINE plans only take into account the number of ACTIVE horses you have, not Reference ones.