Re: What animals lay the largest/smallest eggs?

Dear Beth,
I'm assuming that you're asking about animals currently living? I'm also 
assuming that you're interested in animals that lay eggs that are already 
fertilized?  If so, then ostriches do lay the largest eggs and I believe 
hummingbirds (though I'm not sure which one) lay the smallest.  Your best 
bet to check this and get sizes is to look through a book on birds or phone 
your local museum, the natural history department. There are also insects 
species that lay smaller eggs and nematodes (roundworms,which technically 
are animals)--they lay eggs around 0.02 mm.