Hi,
You can't enter a range of dates. However, you can:
- use the "start" and "end" input fields of the "year selector" setting of the date picker custom field to limit the selection of the dates to the current year (if that's a requirement)
- use the "exclude dates" textarea to enter the list of dates you don't want to be selectable. And you can specify only the day of the month and the month (not the year) in the dates of that field so it will also apply to all the years, avoiding having to enter the dates for every year in the future.