I don't know; I visited there in August of 2017 and there were Straw-necked Ibis, Silver Gull, Laughing Kookaburra, and Black Swan in the aviary at that time. My guess is that only the Silver Gulls and Black Swans would be cold-hardy in northern Kansas.
The aviary was open for walkthrough in June with the same species listed above. Perhaps it is closed for walkthrough in colder months as an extra precaution against HPAI (which is more prevalent in the cold)? Just a theory, I don’t have any concrete evidence