Don't be too hard on the storks Irenekl, it is what they do and they are far from the only ones - eagles here do the same thing.
Here's some background information on White Stork reproduction:
A White Stork pair raises a single brood a year. The female typically lays four eggs, though clutches of 1–7 have been recorded. Incubation begins as soon as the first egg is laid, so the brood hatches asynchronously, beginning 33 to 34 days later (about the same as peregrines). The first hatchling typically has a competitive edge over the others and while stronger chicks are not aggressive towards weaker siblings, as is the case in some species, weak or small chicks are sometimes killed by their parents (called infanticide). This behaviour occurs in times of food shortage to reduce brood size and hence increase the chance of survival of the remaining nestlings. White Stork nestlings do not attack each other (sibling killing is called siblicide), and their parents' method of feeding them (disgorging large amounts of food at once) means that stronger siblings cannot outcompete weaker ones for food directly, hence parental infanticide is an efficient way of reducing brood size. Despite this, this behaviour has not commonly been observed.
