Oats are generally considered the best grain food for horses. Good oats are heavy, have a thin skin, and are clean, hard, sweet, and free from musty smell. Ordinary oats usually contain about 30 per cent. of innutritious husk; and light oats, weighing less than 40 lbs. to the bushel, contain a larger amount of husk than heavier oats. White oats are generally thinner in the skin than black. Very good oats will weigh from 42 lbs to 48 lbs. per bushel; but under 40 lbs. they are not of much value for hard work, unless given in larger quantity. Kiln-dried oats are objectionable, inasmuch as the flour in them is more or less damaged, either in the process of drying or before they have been put on the kiln. Foreign oats, however, are generally slightly kiln-dried, even when in good condition, before being put on board ship, with a view to prevent their heating during the voyage. Oats, also, which have been badly harvested, or become dirty from any cause, are sometimes washed to improve their appearance, and then dried on the kiln. New oats are also sometimes slightly kiln-dried to make them hard, resembling old oats, and thus increase their value. When so dried, oats have a peculiar smell and taste, and a wrinkled appearance about the ends of the husks, owing to the shrinking of the kernel; the colour is also deeper, and sometimes reddish in tint. What are called "foxy" oats are oats which have heated in bulk when not perfectly dry, and undergone fermentation to some extent. They have a pink or very red colour, an unpleasant smell, and a bitter taste. When given to horses they act injuriously upon the kidneys, causing diabetes and loss of condition. Damp oats are generally recognised by their softness, mustiness, or mouldiness, or sprouting, depending upon the amount of damp, the period of exposure, and whether the oats are in bulk. If merely soft, no great harm is done, but if they have a musty smell, or show mould, then they are unfit for food. Sprouted oats should not be given for food. Oats may be mixed with stones, dirt, or any foreign matter, as well as the small seeds of weeds. These should be got rid of by winnowing. New are chiefly distinguished from old oats by the smell, which in the former is rather earth-like; the husk of the new oat is also bright, while its taste is sweet and milky; it is likewise softer than the old oat.