"Being stunned causes animals to suffer longer painful death and its not humane at all"
What nonsense, please provide evidence to back that up. Below is the CSIRO's findings which are the exact opposite to your claim. Essentially their findings found stunning removed all pain yet slaughter without stunning resulted in pain for periods between 10 and 30 seconds.
"However, EEG measurements indicated that animals in the unstunned slaughter group were likely to have experienced conscious pain up to 30 seconds post slaughter."
http://www.mla.com.au/Research-and-d...eef-Cattle/935