The Prophet ﷺ permitted the shepherds to throw the pebbles one day and skip the next.
حدثنا سفيان بن عيينة عن عبد الله بن أبي بكر عن أبيه
أن النبي ﷺ رخص للرعاء بأن يرموا يوما ويدعوا يوما
Its isnad is sahih. Abdullah bin Abu Bakr is the son of Muhammad bin Amr bin Hazm the Ansari, and both he and his father are trustworthy, with their hadith found among the six major collections. His father's kunya is his name. Abu Bidah bin Asim is trustworthy, and his hadith is found in the Sunan.The hadith was narrated by Abu Dawud, 2/202, no. 1976, in the book of Hajj, on stoning the pillars.