Ours is the small Ifor Wiliams trailer, can be converted from animal carrier (with roof & ramp, loading gates), to flatbed to highsided mesh - really good workhorse on the holding - takes up to 8 medium sized adult sheep or up to 16 square bales of hay. Can also be (wo)man-handled when empty - good for my trailer-manouvering abilities (or lack of it!).
it is easier to have a ramp for the animals to walk up, especially if heavily in-kid/lamb, and for transporting anything to the abattoir you will need a ramp and side gates.