The Passover Sacrifice' is a ritual slaughter within the context of a religion to commemorate a specific event – the blood of the lamb marking a protective sign to be spared the plague visited upon Egypt.The sheep being led to slaughter would be eaten or sold by the family, or maybe given to someone, but not as a sacrifice for sins.
It's a sacrifice, in this instance a peace offering – to stay the hand of the avenging angel – rather than sin offering.