If grass hay is not available, you can feed a legume hay, such as alfalfa, though in general you should avoid this as much as possible.

如果干草是无法使用的，你可以给一个豆类植物的干草，如苜蓿，但一般来说，你应该给猪猪尽可能少的食用这种草。

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When the researchers examined the ratio of N15 within the tissue of earthworms offered legume seeds, it decreased significantly, demonstrating that earthworms feed upon, and prefer, legume seeds and seedlings.

BBC: Earth News - Earthworms eat live seeds and plants, scientists find