There is no requirement to say a blessing before the animal is slaughtered.
We can assure you that all of the meat on the McDonalds UK menu is sourced from carefully selected and approved abattoirs that are compliant not just with EU welfare regulations but with McDonalds own rigorous quality, hygiene, food safety, animal welfare and traceability standards. Third party audits and frequent audits from our suppliers confirm that these high standards are in place. This includes adhering to specific legislation and associated guidance on animal welfare during transportation and slaughter. We are committed to continually improving animal welfare within our supply chain, working with leading independent animal welfare experts and make decisions based upon science to promote continuous improvement as part of our broader sustainable sourcing programmes.
Source: McDonald’s FAQ