Animal sacrifice is the ritual killing of an animal as part of a religion; it is practice by many religion including Hindu.
In Nepal we mostly see Chicken and Goats being offered to god at Dashai and in shakti peeth temples like Manakamana and Dakshinkali. This Particular picture is from dakshinkali.
In my opinion these practice should be discourage as being a human being and offering animals to god is not right.
In our culture we have a option of coconut instead of animals, so why to kill an innocent animal.