Hadith: He asked: May I pray in the sheepfolds? He replied: Yes. He then asked: May I pray where camels sit? He replied: No

عن جابر بن سمرة رضي الله عنه أن رجلا سأل رسول الله صلى الله عليه وسلم أَأَتَوضأ من لحوم الغنم؟ قال: «إن شِئْتَ فتوضأْ، وإن شِئْتَ فلا تَوَضَّأْ» قال أتوضأ من لحوم الإبل؟ قال: «نعم فتوضَّأْ من لحوم الإبِل» قال: أُصَلي في مَرَابِضِ الغَنم؟ قال: «نعم» قال: أُصلي في مَبَارِكِ الإبِل؟ قال: «لا».
[صحيح] - [رواه مسلم]

Jābir ibn Samurah (may Allah be pleased with him) reported that a man asked the Messenger of Allah (may Allah's peace and blessings be upon him): "Should I perform ablution after eating the meat of sheep or goats?" He replied: "If you wish, perform ablution, and if you do not, then do not perform it." The man then asked: "Should I perform ablution after eating camel meat?" He replied: "Yes, perform ablution after eating camel meat." The man again asked: "May I pray in the sheepfolds?" He replied: 'Yes.' He then asked: "May I pray where camels sit?" He replied: 'No.'
Sahih/Authentic. - [Muslim]

Explanation

One of the Companions of the Prophet (may Allah's peace and blessings be upon him) asked him about the meat of sheep and goats; whether it is obligatory to make ablution after eating it if one wants to pray or do something that requires purification. "If you wish, perform ablution, and if you do not, then do not perform it": the Prophet (may Allah's peace and blessings be upon him) gave him the choice either to perform ablution or not to perform it because both options are permissible. "Should I perform ablution after eating camel meat?": i.e. is ablution obligatory for the one who eats camel meat if he wants to pray or do something that requires purification? 'Yes, perform ablution after eating camel meat': i.e. it is obligatory for you to make ablution after eating camel meat, even if what you eat is a small amount. As for camel milk or soup, it is not obligatory to make ablution after consuming them, because the Prophet (may Allah's peace and blessings be upon him) did not order the people from the tribe of ‘Arinah to make ablution after drinking camel milk when he ordered them to drink it, and delaying the clarification of something beyond the time of need is impermissible. He again asked: "May I pray in the sheepfolds?" i.e. is prayer permissible in the places where sheep rest? The reply was in the affirmative; i.e. it is permissible to pray in those places because they (the sheep) are not feared. He again said: "May I pray where camels sit?" The reply was in the negative; i.e. do not pray there, because you will not be safe from the camels' wildness and they might harm you while you are praying by bumping into you or the like. However, this is not the case with sheep because they are peaceful calm animals that do not harm people.