There is no zakaah on an’aam animals unless they grazed for the whole year or most of it
Question

I have camels and sheep which graze for part of the year and are fed by me for the other part. Is zakah due on them or not?.
Praise be to Allah.We have already stated in the answer to question no. 40156 that zakah is not due on an’aam animals [i.e., camels, cattle, sheep or goats] unless they graze for all or most of the year. But if they are fed for half of the year or more, then no zakah is due on them.  
Ibn Qudaamah said in al-Mughni: 
The view of our imam (i.e., Imam Ahmad) and the view of Abu Haneefah is that if they graze for most of the year, then zakah is due on them. Al-Shaafa’i said: If they do not graze for the entire year then no zakah is due on them, because grazing is a condition of zakah being due, so it should be year-round. We have the general meaning of the texts which indicate that zakah is due on livestock. The definition of grazing is not cancelled out if a little fodder is given to the animals, and does not mean that they are not included in this report, because giving a little fodder sometimes cannot avoided, and feeding year-round will waive the zakah altogether; because owners of grazing animals cannot avoid giving their livestock fodder sometimes, such as on cold days and when it snows. 
From al-Mawsoo’ah al-Fiqhiyyah, 23/250. 
Shaykh al-Islam Ibn Taymiyah was asked about a man who had camels and rented pasture for them during the grazing season – is zakah due on it? 
He replied:  
If they graze for most of the year, and he rents pasture for them for three or four months, he has to pay zakah on them. This is the more clear of the two scholarly opinions. Majmoo’ al-Fatawa, 25/48. 
Shaykh Ibn Baaz (may Allah have mercy on him) was asked: 
A man has one hundred camels but for most of the year he feeds them. Is zakah due on them? 
He replied: 
If the flock of camels, cattle or sheep does not graze for the whole year or most of the year, then no zakah is due on them, because the Prophet (peace and blessings of Allah be upon him) stipulated that for zakah to be due, the animals should be grazing. If their owner feeds them for most of the year or half of the year, no zakah is due on them, unless they are for trading, in which case zakah is due on them as trade goods, as in the case of land, cars, etc that are prepared for sale, if their value reaches the nisaab of gold or silver. 
Shaykh Ibn ‘Uthaymeen said in Fatawa al-zakah (49): 
Flocks which are fed for half the year are not subject to zakah, because the zakah on livestock is only due on animals that graze on plants that Allah causes to grow on the ground for the whole year or for most of the year. But if they are fed for part of the year or half the year, then no zakah is due on them. But if they are prepared for sale, then they come under the ruling on zakah on trade goods. If that is the case, then they are subject to zakah when their value is estimated each year, then one quarter of one-tenth of their value should be paid, i.e., 2.5% of their value. 
It says in al-Sharh al-Mumti’ (6/32): 
If a person has camels that graze for five months and are fed for seven months, then no zakah is due on them. If they graze for six months and are fed for six months, then no zakah is due on them. If they graze year-round, then zakah is due on them. If they graze for seven months and are fed for five months, then zakah is due on them. 
It says in Fatawa al-Lajnah al-Daa’imah (9/214): 
zakah is due on grazing sheep, if they graze for the whole year or most of it.