I don't think we need to go as far as to remove the brain. But let's say we map all the pain receptors and pain-like receptors(like loneliness) and engineer a

I don't think we need to go as far as to remove the brain. But let's say we map all the pain receptors and pain-like receptors(like loneliness) and engineer a chicken without those or with them blocked ? It's a doable thing with today's tech,similar things are already been done to lab mice. hopefully that chicken lives. Would it be ethical to kill such a chicken?