I found a blue egg with brown speckles outside my house there was no nest around wat shud i do to care for it?

whatever was in the egg is dead now..... don't waste your time caring for it..... without a mom bird sitting on it, incubating it, it got cold and died..... nothing you can do about it..... especially if it was on the ground overnight for hours.....you can keep it if you like, for a souvenier, but it's nver going to hatch.....