“The Lord established the principle of tithing among the Israelites by referring to the method by which shepherds counted the sheep [Leviticus 27:32].
When sheep were herded into a sheepfold at night, the shepherd stood by with a rod saturated with dye. He marked every tenth sheep with this dye as they entered the pen. This enabled him to do a quick count to determine if any were missing.”
(Knight, George W. 2007. Bible Customs & Curiosities, p. 56).