No ritual, whoever conducts it, is going to do any good either to the animal or to the diner. Let man do what he must to assuage his hunger. If what he gets, he puts to good use and shares with the needy, then it is well used and well spent, otherwise not. The reason why meat is not served at langar in the Gurdwaras is because langar is supposed to be a symbol of equality of mankind where all people no matter what race, religion or caste can eat toghether in the atmosphere of brotherhood. Hindu, Sikh, Muslim, it does not matter who they are.
Different religions have different dietary restrictions.
Hindus cannot eat cow, muslims cannot eat pork and will only eat halal meat. Jews will only eat kosher meat, others cannot eat fish or eggs. But in a gurdwara langar, it does not matter what their dietary taboos or religious beliefs are, the food is designed so that all can eat together and no one will be offended or not be able to partake of the meal. No graphics or photographs from The Sikhism Home Page may be reproduced or used on another web site or for any other means without express written permission from Sandeep Singh Brar.