The smallest egg my chickens have laid weighed 13 grams! That was about half the size of the next smallest. And it did have a yolk, too. The shell was dark brown. It got smashed so I couldn't blow it out. I had seen it earlier in the day as it was just laying on the ground in the barnyard. I had thought it was an avocado pit since sometimes I feed the girls avocados. Then later I saw that something had broken it open and I could see the yolk and realized it wasn't an avacado pit. Tiny!