I would recoment to visit in summer ( did it, and ejoyed) , because in winter all crocodiles are indoors, and all your visit will take no more then 15min if you miss the guides speech, if you lucky to come at the time guide doing show all visit will take 40min.
I do not recomend visiting in winter, unless you happy to support the park, as tickets for 3ppl = 52euros.