On average, it takes a hen about 24 to 26 hours to produce and lay one egg. This process includes the formation of the yolk, egg white (albumen), membranes, and the calcium-rich eggshell, with the shell formation alone taking around 20 hours

. After laying an egg, it typically takes about 15 to 30 minutes for the hen to start the process again

. The egg formation stages occur as follows:

• Yolk release and fertilization (if a rooster is present) take about half an hour.
• The egg white forms over approximately 3 hours.
• Membranes and initial shell formation take 1-2 hours.
• The final shell hardening in the uterus takes 20-21 hours.
• Just before laying, a protective bloom is added to the egg

Hens usually lay eggs during daylight hours, influenced by light exposure, needing about 14-16 hours of light daily to maintain egg production. This light dependency causes the egg-laying cycle to shift slightly later each day, sometimes resulting in a skipped day if the hen lays too late in the day

. In summary, from start to finish, a chicken takes roughly a full day-24 to 26 hours-to lay an egg.