With plastic eggs so easy to find this time of year, I thought that I could find something educational to do with them. My boys are always up for an egg hunt, even if there isn't candy and such involved, so that was an easy starting point. I wanted to fill the eggs with small toy plastic animals that hatch from eggs -turtle, lizard, snake, bird, fish and the like, but I didn't have the time for a small toy search and ended up putting in pictures of the animals.
Once the egg hunt was over, and interest peaked, we talked about the different kind of eggs that animals lay. I read to them Ruth Heller's Chickens Aren't the Only Ones. If you have not read this book before, it is a must for the pre-K to 2nd grade crowd, although even my older kids like it because of its vividly colored and beautiful drawings.
We then went over classification and talked about the characteristics of each class. We then divided the animals according to their characteristics. We talked about the exceptions to the descriptions of the classes such as the egg-laying mammals. They were a little surprised to find out that there were egg-layers in each of the classes.