Why did President Woodrow Wilson keep sheep at the White House?

The sheep at the White House were part of the war effort.

In 1917, during World War I, President Wilson arranged for a small flock of sheep to graze on the White House lawn, thus freeing up the regular gardeners for military service.

Although the sheep began eating more of the White House grounds than the lawn, the Wilsons continued to defend them, citing, among other things, the vast amounts of “White House wool” the sheep generated for the Red Cross.