Fiqh-us-Sunnah Volume 3, Zakaat and Fasting, Fiqh 3.039A.
There is no zakah on camels unless there are five of them, they have been grazing freely and they have been in one’s possession for a year. When the camels are five, their zakah is one sheep (shah).
When they are ten, their zakah is two sheep. Thus, every time they increase by five, the zakah due on them is one more sheep. However, when they reach twenty-five, the due zakah is a she-camel (bint makhad or bint labun) which is a year old and starting the second, or a young male camel which is two years and already starting the third year. When they reach thirty-six, the zakah due on them is a young she-camel (bint labun). When they reach forty-six, the due zakah is a she-camel (huqqah) which is already three years old and starting the fourth. When they reach sixty-one, the due zakah is a four year old camel already starting its fifth year (jazh’ah). When they reach seventy-six, two young she-camels (bint labun) are due. When they are in the range of ninety-one to 120, the zakah is two young camels (huqqatan). When the number of camels is above 120, on every forty young she-camels, one bint labun is due. And on every fifty above 120, a young she-camel (huqqah) is due.
When the ages of camels offered for zakah differ, the owner should pay jazh’ah. If he does not have it, he may pay huqqah and may add two sheep or twenty dirhams provided he can afford to. The person who has to pay huqqah as zakah but does not have it only has to pay jazh’ah. The zakah collector, then, will pay him the difference, which is twenty dirhams or two female sheep. The one who has to pay huqqah and does not possess it can pay just the bint labun if he has it, along with two sheep if they are available. If not, he may pay twenty dirhams. If he has to pay the zakah of bint labun and does not have it, he can pay a huqqah and will receive from the zakah collector twenty dirhams or two sheep. If he has to pay the zakah of bint labun but has only bint makhad, it will be accepted from him along with two sheep if they are available, or twenty dirhams. If he is liable for the zakah of bint makhad and does not possess it, a ibn labun will be accepted from him without any additional things. If he has only four camels, he is not supposed to pay anything unless he wants to.
These are the rules concerning zakah on camels which were applied by Caliph Abu Bakr as-Siddiq, and none of the companions differed with him in this matter.
Az-Zuhri reported, on the authority of Salim from his father: “The Messenger of Allah, upon whom be peace, had the rules of sadaqah written down but could not send them to his governors. Then, after his death, Abu Bakr dispatched them and applied them, a practice which Caliph ‘Umar also followed and wanted others to follow, as indicated in his will.”