"剔出来杀掉的动物" can be translated into English as "animals selected for slaughter" or, depending on the context and desired nuance, "animals that are culled for killing".
"Animals selected for slaughter" is a straightforward and commonly used expression, indicating that certain animals have been chosen to be killed, typically for meat or other products.
"Animals that are culled for killing" conveys a similar meaning but with a slight emphasis on the process of selection or removal (culling) from a larger group before being killed.
Both expressions are appropriate, and the choice between them may depend on the specific context and the level of detail or emphasis you wish to convey.