The most relevant parts of that article ( a rai is 1600 square metres):
The AGENCIES in charge of Dusit Zoo in Bangkok yesterday confirmed that there is a plan to move the zoo to another site in Pathum Thani province, but refused to divulge details or make any comments.
His Majesty King Maha Vajiralongkorn on Thursday granted the deed for 300-rai plot in the Klong Hok area of Pathum Thani’s Thanya Buri district, to be used for the new zoo and the new head office of the Zoological Organisation of Thailand.
....
It has been reported that all animals in Dusit Zoo would be moved to the new zoo by 2019 at the earliest, because Dusit Zoo is too small for the increasing number of visitors.