When the turnips allotted to the sheep, which seldom exceed a week's supply, are consumed, another portion of the field is enclosed; while the shells are torn up with a two-pronged hook, and either left there to be consumed by the flock, or carted to another field for the use of sheep not then intended to be fattened. A fresh supply should always be afforded them before the old one is eaten clean, otherwise their fattening will be much retarded. It is usual to allow them at the same time plenty of salt, placed up and down the field in troughs or boxes,[21] and about a ton of hay in the ten or fourteen days, to every hundred sheep; though that number, if supplied with what, and permitted to run about, will consume that quantity in a week. In spring, from half a pound to a pound of oil cake is given daily to each of them, along with turnips. [21] Old casks, wanting ends, form the best of all contrivances for holding salt for sheep, as when laid on their sides, and retained in that position by stakes, they allow the sheep free admission, at the same time that the salt is defended from rain. In places where the cold during spring is any way severe, the Swedish turnip ought always to be preferred for feeding sheep, as from the formation of the upper part of the bulb, water cannot collect within it as it does in other varieties, to their serious injury when frost sets in. Turnips must be cut for such sheep as are shedding their teeth. The mouths of those that refuse to eat them should be examined, that in the event of a tooth being loose or broken it may be removed. Occasionally a sheep will be unable to gnaw a turnip, owing to a peculiar formation of the head, the lower jaw being so very short as to give the profile some resemblance to that of a pig. Such deformed animals are said in this quarter to be _grun_-(ground)-mouthed: I believe from the elongation of the nose suiting them better for poking in the earth than for feeding in the usual way.