"Laid eggs" can be substituted with a variety of synonyms depending on the context and species. For example, birds are known to "lay eggs," while fish "spawn," and reptiles "deposit" eggs. Other synonyms might include "produce," "lay down," "birth," "lay out," "generate," or "hatch." Each of these words conveys the same meaning of an animal giving birth to an egg or eggs, but they have subtle differences in tone and emphasis. Using appropriate synonyms can add variety and depth to your writing, making it more engaging and informative for readers.