I don’t know the answer to this but I’m interested to hear what others have had. I have a sulcsta In her second year of egg laying all egg to this point have be round but In the last clutch there were several that were shaped like chicken eggs very interesting!
I don't know why, but different species lay different-shaped eggs. The Manouria and leopard eggs look exactly like little ping pong balls while the RF eggs look more elongated. If memory serves correctly, when I had Russian eggs several years ago, they looked like white pecans.
I don't have experience with tortoise eggs, but when chickens first start laying eggs there can be variability in the shape and size. Even after a time, there would still be the occasional strangely shaped egg.
I'm not sure if:
Tortoises lay eggs.
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Chickens lay eggs.
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Chickens can lay weird eggs at the beginning.
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Tortoises can lay weird eggs at the beginning of their egg laying.