A group of lambs (baby sheep) is still called a flock, though some folks cheekily call it a “kiddie herd.” That’s not official, but I’m making it official right now. I’ve also heard “a bouncing” as a fun descriptor, but you might get some weird looks using that in the real world.
What Is a Group of Sheep Called? It’s More Than Just a Flock - Ponderworthy
And here’s a quirky bonus: if you ever see a group of ewes (female sheep) with their lambs, that’s sometimes called a family. Aww. Nature is sweet until one of them steals the last mouthful of clover.
The One Name You Should Never Use (Warning!)
Whatever you do, don’t call a group of sheep a “party.” I tried this once at a petting zoo, and the sheep just stared at me blankly. They clearly hadn’t RSVP’d. Trust me, sheep are terrible party planners. They show up late, eat all the hay, and leave no time for dancing.