Thailand – Poor Birds

In some Thai temples, I’ve seen something really upsetting;
I understand it may be part of culture, history or religion, but I still don’t like this idea.
So, there are people selling you birds in cages. When you buy a bird and release it “you will have goodluck and happiness in your life forever” (original writing).
The point is those birds have on purpose broken wings or kind of injuries, so they cannot fly too far. And after “you give the freedom to birds”, the seller will catch them again and sell to another person, and so on!