Biologists have long debated about whether egg production in birds is biologically highly costly, some theorizing that egg production is energetically or nutritionally demanding.

长期以来，生物学家一直在争论鸟类的产蛋在生物学上是否具有很高的成本，有的理论认为产蛋对能量或营养的要求很高。

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You see, adult female birds during egg production produce a layer of spongy bone tissue inside certain long bones.

你看，成年雌鸟在产蛋的过程中会在某些长骨内产生一层海绵状的骨组织。

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As we've discussed, birds are apparently descendants of dinosaurs and shared many commonalities with some dinosaur species, like feathers and maybe even flight and of course egg laid.

正如我们讨论过的，鸟类显然是恐龙的后代，与一些恐龙物种有许多共同之处，比如羽毛，甚至飞行，当然还有产卵。

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And to justify why its birds were angry, Rovio added egg-grubbing pigs.

FORBES: Magazine Article

Both Wright County Egg and Hillandale Farms were supplied by another company, Quality Egg, which provided feed and young birds.

CNN: No further egg recalls expected, feds say