The egg was a symbol of the rebirth of the earth in celebrations of spring and was adopted by early Christians as a symbol of the resurrection of Jesus.
The egg is seen by followers of christianity as symbolic of the grave and life renewed or resurrected by breaking out of it. The red symbolizes the blood of Christ redeeming the world and human redemption through the blood shed in the sacrifice of the crucifixion. The egg itself is a symbol of resurrection: while being dormant it contains a new life sealed within it.
For Orthodox Christians, the Easter egg is much more than a celebration of the ending of the fast, it is a declaration of the Resurrection of Jesus. Traditionally, Orthodox Easter eggs are dyed red to represent the blood of Christ, shed on the Cross, and the hard shell of the egg symbolized the sealed Tomb of Christ—the cracking of which symbolized his resurrection from the dead.