Simply put, the female can be without a Drake for a period of 14 days. The reason is because the hen has sperm storage tubules where the hen can store the sperm for a period of 10-14 days. Read below for more information on how the female accomplishes this.
Most birds have only one ovary and one oviduct. In early stages of embryonic development, each female bird has two ovaries; only the left one develops into a functional organ. In some birds, such as hawks, the right ovary and oviduct usually develop. A mature ovary looks like a cluster of grapes. and may contain up to 4,000 small ova which can develop into mature ova.
With fertilization, the ovum (egg) becomes a developing embryo The embryo passes through the oviduct typically takes about 24 hours (for passerines & most other birds). The demand for calcium to make the egg shell is very high, and so the circulating levels of blood calcium in birds are greatly elevated compared to mammals, typically twice as much.
In most birds, only the left ovary and oviduct persist. The ovary enlarges greatly during the breeding season. Active ovaries resemble bunches of tiny grapes -- the developing follicles. The oviduct opens medially to it in a funnel-shaped ostium. Ovulation results in the release of an egg from a mature follicle on the surface of the ovary. The egg, with extensive food reserves in the form of concentric layers of yolk, is picked up by the ostium and ciliary currents carry it into the magnum region. Over a period of about three hours the egg receives a coating of albumen.
The egg then passes into the isthmus, where the shell membranes are deposited. This takes about one hour. The egg them moves to the uterus, or shell gland, where the calcareous shell is added and, in some birds, pigment is added in characteristic patterns. The egg then passes into the vagina and cloaca for laying.
Near the junction of the vagina and shell gland of female birds are deep glands lined with simple columnar epithelium. These are the sperm storage tubules, so called because they can store sperm for long periods of time (10 days to 2 weeks). After an egg is laid, some of these sperm may move out of the tubules into the lumen of the tract, then migrate farther up to fertilize another egg.
Fertilization of the egg usually occurs in the infundibulum.
A chicken's egg can remain in a nest for days, without any outside heat and stay alive. A hen gives her first 12 eggs (this number varies) no care at all until number 13 is laid and then she begins incubation. Once the hen decides to incubate (we're not sure exactly what tells her she now has "enough" eggs) and the embryo starts developing,however, the egg must remain relatively warm or it will not continue development and will die. This arrangement allows all of the chicks to hatch at the same time rather than having the first chick hatch 13 days, for example, ahead of the last chick - pretty neat! http://www.enaturalist.org/topic.htm?topic_ID=5
