They're not supposed to now, at least the ashkenazi aren't.
From the New York Times:
As a mark of respect for the memory of the temple sacrifices, the eating of a whole roasted lamb on Passover is forbidden by the code of Jewish law called Shulhan Arukh, which was first printed in Venice in 1565. Jews who strictly interpret this rule will not eat roasted meat or poultry of any kind for their seder. Mar 23, 1988
[–] 22972210? 0 points 3 points 3 points (+3|-0) ago
White people seriously need to eat more lamb. Why did we ever stop? Classic holiday meal for Christmas and Easter was always a roasted leg of lamb but we don't even do that anymore. People who raise sheep already know that there's like a 80% chance their livestock is going to be prayed over at the slaughterhouse by a jew or a muslim and then bled out while it's still alive and conscious because those savages were taught that their god wants the animal to suffer.
[–] 22973074? 0 points 1 point 1 point (+1|-0) ago
Sheeps are more difficult to raise and keep safe and healthy than cows, pigs, chickens. So its less popular in America
[–] 22973432? 0 points 1 point 1 point (+1|-0) ago
They're not that difficult to raise. I think the main things holding the US back from raising more is that we dont have a lot of people buying it, they're not easy to artificially inseminate (high failure rate) and there's much more infrastructure and support available for cattle (e.g. knowledgable veterinarians, feed suppliers, processors).