Banks give category-based rewards and exclusions based on MCC code which is assigned to the merchant based on the category of products/services they deal with. The list of MCC codes is quite exhaustive as there are codes for every small category. And its not restricted to categories, large hotel and airline brands even have their own codes. In this case Poultry shops have their own code which is 5499. You can find the list of all the codes
here.
A big consumer experience gap in the Indian credit card system is that there is no way for the customer to know the MCC code prior to making the transaction. We can know this only by calling up the customer care after the transaction is settled. I suggest stick to buying chicken from supermarkets. Even then there is no guarantee because another issue is that in many cases the wrong MCC will be assigned to the merchant by the bank, usually the result of some bank employee being a lazy ass. The largest hypermarket in my city for instance is registered under the MCC code of "hardwarehi