Translation:The children in Bavaria have long vacations.
They have six weeks of summer holidays as all school children in Germany. They just have the latest holidays, spanning from August until mid-September, while some other countries start their holidays already in June. Because of this, Bavarian schools have longer holidays around Pentecost, while the other countries have longer holidays in autumn. So if the sentence means Pentecost holidays, it is true.
It's because, in this case, it is "strongly" inflected. Because there is no article before "Ferien", the adjective takes the "-e" ending instead of "-en" (which it takes in pretty much all other cases).
Ferien is always longer, mostly school breaks ranging from one week to six in summer. A single holiday is "der Feiertag" bzw "die Feiertage" in case there are several in a row, like Christmas. It doesn't mean you have to travel for either, just that you don't have school/work.