Most of the time it comes down to the survival of the fittest. That means that even if they have more than one egg, only one of the offspring is going to survive. This is the one that the parents will feed and focus attention on as it has the greatest chance of one day thriving on its own. The specifics of what they will do depend on the food that is available and the type of penguin tending to the offspring. However, penguins are very good parents and give them the attention they need. They also do their best to keep them fed and to keep them safe.