A low-income farmer is looking for an alternative way to make his herd productive. Presently, he is growing Barbados Blackbelly and Dorper sheep and Large white and Landrace pigs. He is thinking of crossing a different breed to his pre-existing herd. What trait is common on the two sheep and two pig breeds? What breed should the farmer choose to make his sheep herd be able to also produce wool? What breed should the farmer choose to make his pig offspring have a trait of an extremely high proportion of lean-to-fat?