The difficulty in assigning paternity is one of the main limits for increasing the efficiency of a selection scheme for sheep breeds. Performing single sire natural mating could be a valid alternative to the use of artificial insemination for pedigree recording for selection purposes or to avoid inbreeding.
Farmers manage the natural mating by grouping ewes with a single ram (“mating group”) during the breeding period.
The ewes of a mating group can be grouped with another ram in the same reproduction season only after a lag of 14 days. This management allows assigning the correct sire to a lamb on the basis of the lambing date. The size of the mating group depends on the ram's sexual aptitude and the planned lambings period.
An essential requirement in the management of multiple single sire mating groups is the physically separation to avoid paternity errors. Some farmers use crayons of different colors to mark the rump of ewes of different single sire mating groups. In this way they are able to visually detect even from far, an accidental mixture of different single sire mating groups.