I know what you are thinking--a silly theme for a unit. When I was in class for my teaching certification, one of the instructors talked about her favorite unit to do with the kiddos: bread. Yes, sounds silly but there are actually a lot of books about bread. So I tried building up my unit repertoire with ones that include foods--bread, pancakes and my all-time favorite---eggs.
Some books that I love to use:
These birds are arguing over the "egg" they found and in staking their claim end up becoming friends in the process. A great surprise ending when the "egg" turns out to be a ball.
Funny story about a cat trying to procure an egg for his dinner. Instead he gets 3 very multicultural birds. Too cute!
Non-fiction with lots and lots of pics of various different kinds of eggs.
About how different organisms grow.
Some critical thinking activities:
1) Of course the always popular egg drop competition. I usually ask for the students to bring various materials and then work cooperatively in groups to create their egg casings.
2) Fragile or not. Eggs are often thought of as being very fragile-but the kids are always amazed at how much weight an egg can hold when you sit it upright and place books on it-you can usually put a lot of books on it before it cracks. Strong enough to care for that little baby inside.
3) Let them ponder the age-old which came first, the chicken or the egg.
4) Give them cut-outs that look like eggs and have them do some divergent art and come up with an animal or object the egg can be part of.
Multiple perspectives: obviously the egg but you can also do the nest or the baby inside, farmer collecting all the eggs.
Rules: What are the rules of an egg and then the students can try to invent their own kind of egg casing using those same rules.
Creativity: Eggshell Mosaics-I'm going to try this for the first time this year. You are supposed to color the egg and then poke a little hole in it, rinse it out and then flatten it with a rolling pin. The kids use the shells to make a design.