I googled it and found this:
Though it may sound strange, the Bible does indicate that animal sacrifices will take place during the millennial kingdom. Ezekiel 43—46 offers the most developed prophecies regarding these practices as it deals with the Jewish temple that will exist during the millennial kingdom and what takes place in it. Specifically, the line of Zadok will offer sacrifices (44:15). Specific animal sacrifices are described in chapters 45—46 and include rams, lambs, and bulls.
In addition to Ezekiel, Isaiah discusses sacrifices in the future millennial kingdom, stating: "their burnt offerings and their sacrifices will be accepted on my altar" (Isaiah 56:7). Zechariah 14:16 adds, "Then everyone who survives of all the nations that have come against Jerusalem shall go up year after year to worship the King, the LORD of hosts, and to keep the Feast of Booths." This celebration would also include animal sacrifices. Jeremiah 33:18 notes that during this time period, "the Levitical priests shall never lack a man in my presence to offer burnt offerings, to burn grain offerings, and to make sacrifices forever."
... So carry on. I stand corrected. (and this is why I tend to avoid eschatology topics).