We have old Danish farm hens. They are extremely hardy, but not as prolific egg-layers as other breeds. Their eggs are generally smaller as well.
Elora, the lowest ranking hen, lays the most and the biggest eggs. Her eggs are almost the size of the regular organic eggs you can buy in the supermarket, and she'll usually give us 4-6 a week.
Yvaine is the queen and the boss. Her eggs are slightly smaller than Elora's, but she's a good girl and lays 3-5 eggs a week.
Isabeau... Isabeau lays eggs when she feels like it. Usually 2-4 a week. Her eggs are smaller and more oval than the other two's so there is never any doubt about which eggs are Isabeau's. This week, however, she's laid the tiniest eggs, they are so small that they won't even fit into an egg holder. We began joking that Isabeau must be half sparrow.
Here's one of the small eggs, next to one of Yvaine's:
Well... Isabeau must have heard us because today she took revenge with a giant egg! Look at it next to the same egg of Yvaine's:
And here are two of Isabeau's eggs together, the small and the large: