From Reddit: "This is actually pretty cruel, they put a small amount of food on the beam above their heads, but when they go for it they just fall and slide down. They would get so tired and hungry after like 2 minutes."

Most of the Redditors don't agree that it's cruel.

Redditors also say that ducks need a lot of exercise:

Ducklings are pretty active on their own, provided they have enough space to move around. They're always either running, sleeping, pooping or eating. I don't think that the sole purpose of this would be exercise, it would definitely be entertainment, but that said, zpridgen75 is right in saying that this is most likely not the only way they are fed.

Also, ducklings poop on everything:

After the 74,000th time you just kind of learn to deal with it. All they really eat is grains and grass, so it doesn't smell that bad. Occasionally I'll pick up duckling poop with my hands, it's small mushy grains, so it's not that big a deal to me as long as I wash my hands afterwards. Anything they poop on can be washed, except your heart.

Aww...