Religion does not exempt someone from having to follow the laws of the land which they live in. The Buddhist monks are showing a disregard for the laws of their country and the lives of these tiger cubs. They obviously know they are doing wrong since they are hiding the tiger cub bodies.
The monks at the Buddhist Temple should not be exempted from punishment in the deaths of the cubs, regardless of whether they are directly responsible. Allowing the tigers to be housed at the temple makes everyone responsible for their care. Thirty cubs dead means there is a known issue among the tigers, whether it be illness, or neglect.
Yes, the monks should be arrested. If this kind of activity was being overseen by the affiliated members of the temple, then their presumed credibility and virtue would allow for similar heinous acts in the future if not regulated. Animal cruelty applies to all institutions and should be controlled with respect to law, rather than religious beliefs.
While the crimes occurring at the Buddhist temple are reprehensible, there are multiple monks involved with the temple. Proof of involvement with the crime needs to be established before they are all arrested for the act. Arrests should be made based on evidence of involvement but not based on residency at the temple alone.