The temple is open for worship throughout and people can perform pooja on their own.
Lord Shiva was in Mandarachal and Kashi was ruled by a very pious and religious King named Divodas. In his Kingdom every one was very happy and there was all round prosperity. He had reached an understanding with Lord Brahma that as long as he was ruling, Devas and other celestial beings should stay away from Kashi and should not create any disturbance in Kashi. Lord Brahma more or less agreed to it but on one condition that King Divodas should prove to be an excellent administrator and all people living in Kashi and visiting Kashi should be treated well in their religious pursuits.
The King agreed and accordingly gave excellent governance. Lord Shiva was very upset at being away from Kashi for a long time and he wanted to make King Divodas commit some mistake. Accordingly, he sent sixty four Yoginis to create some disturbance, but they were enthralled by the beauty and serene surroundings of Kashi which appeared to be a part of heaven. They ultimately settled down there.
When the Yoginis failed to return, Lord Shiva sent Lord Surya with instructions to create some disturbance in Kashi so as to defeat King Divodas in his resolve. Lord Surya came to Kashi and disguised himself as an astrologer, a learned scholar, a religious propagator, a businessman, a brahmin etc. But he could not find any fault with any person in Kashi or the governance of King Divodas. Lord Surya was also very much attracted towards Kashi and the beauty of the city. Lord Surya thought, if he went back to Mandarachal without fulfilling the wishes of Lord Shiva, the latter would get angry.
Lord Surya finally decided to stay in Kashi. He said to himself, disobeying the instructions of Lord Shiva is a sin, but by staying in Kashi and undertaking religious activities, such sins will easily get cleansed. Accordingly Surya settled down in Kashi for the time being. When Lord Surya did not return, Lord Shiva sent Lord Brahma to Kashi with the same mission. Lord Brahma also did not return. Then Lord Shiva sent several of his Shiv Gans to Kashi in batches. These Shiv Gans arrived at Kashi and they also found the place enchanting.
They installed several Shiv Lings and started performing pooja of these lings. When the first batch did not return, subsequent batches of Shiv Gans were sent and they also did not return. In one of the batches one Shiv Gan known as Kukkut arrived at Kashi and being enthralled by the beauty of the divine surroundings, installed a Shiv Ling which was named after him as Kukkuteshwar and started praying to Lord Shiva.
Kashi Khand, Chapter 53 states that a person who worships egg shaped Kukkuteshwar will attain all happiness and will not have residence in womb (there will be no rebirth).