By daily attention to cleanliness, a few fowls may be kept in such a covered shed, without having any open run, by employing a thick layer of dry pulverised earth as a deodoriser, which is to be turned over with a rake every day, and replaced with fresh dry pulverised earth once a week. The dry earth entirely absorbs all odour. In a run of this kind, six square feet should be allowed to each fowl kept, for a smaller surface of the dry earth becomes moist and will then no longer deodorise the dung. Sifted ashes spread an inch deep over the floor of the whole shed will be a good substitute if the dry earth cannot be had. They should be raked over every other morning, and renewed at least every fortnight, or oftener if possible. The ground should be dug and turned over whenever it looks sodden, or gives out any offensive smell; and three or four times a year the polluted soil below the layer, that is, the earth to the depth of three or four inches, should be removed and replaced with fresh earth, gravel, chalk, or ashes.[2] The shed must be so contrived that the sun can shine upon the fowls during some part of the day, or they will not continue in health for any length of time, and it is almost impossible to rear healthy chickens without its light and warmth; and it will be a great improvement if part of the run is open. Another shed will be required if chickens are to be reared.
Fowls that are kept in small spaces or under covered runs will require a different diet to those that are allowed to roam in fields and pick up insects, grass, &c., and must be provided with green food, animal food in place of insects, and be well supplied with mortar rubbish and gravel.
The height of the wall, paling, or fencing that surrounds the yard, and of the partitions, if the yard is divided into compartments for the purpose of keeping two or more breeds separate and pure, must be according to the nature of the breed. Three feet in height will be sufficient to retain Cochins and Brahmas; six feet will be required for moderate-sized fowls; and eight or nine feet will be necessary to confine the Game, Hamburg, and Bantam breeds. Galvanised iron wire-netting is the best material, as it does not rust, and will not need painting for a long time. It is made of various degrees of strength, and in different forms, and may be had with meshes varying from three-fourths of an inch to two inches or more; with very small meshes at the lower part only, to keep out rats and to keep in chickens; with spikes upon the top, or with scoloped wire-work, which gives it a neat and finished appearance; with doors, and with iron standards terminating in double spikes to fix in the ground, by which wooden posts are divided, while it can be easily fixed and removed. The meshes should not be more than two inches wide, and if the meshes of the lower part are not very small, it should be boarded to about two feet six inches from the ground, in order to keep out rats, keep in chickens, and to prevent the cocks fighting through the wire, which fighting is more dangerous than in the open, for the birds are very liable to injure themselves in the meshes, and, Dorkings especially, to tear their combs and toes in them. If iron standards are not attached to the netting, it should be stretched to stout posts, well fixed in the ground, eight feet apart, and fastened by galvanised iron staples. A rail at the top gives a neater appearance, but induces the fowls to perch upon it, which may tempt them to fly over.
Where it is not convenient to fix a fence sufficiently high, or when a hen just out with her brood has to be kept in, a fowl may be prevented from flying over fences by stripping off the vanes or side shoots from the first-flight feathers of one wing, usually ten in number, which will effectually prevent the bird from flying, and will not be unsightly, as the primary quills are always tucked under the others when not used for flying. This method answers much better than clipping the quills of each wing, as the cut points are liable to inflict injuries and cause irritation in moulting.
The openness of the feathers of fowls which do not throw off the water well, like those of most birds, enables them to cleanse themselves easier from insects and dirt, by dusting their feathers, and then shaking off the dirt and these minute pests with the dust. For this purpose one or more ample heaps of sifted ashes, or very dry sand or earth, for them to roll in, must be placed in the sun, and, if possible, under shelter, so as to be warm and perfectly dry. Wood ashes are the best. This dust-heap is as necessary to fowls as water for washing is to human beings. It cleanses their feathers and skin from vermin and impurities, promotes the cuticular or skin excretion, and is materially instrumental in preserving their health. If they should be much troubled with insects, mix in the heap plenty of wood ashes and a little flour of sulphur.
A good supply of old mortar-rubbish, or similar substance, must be kept under the shed, or in a dry place, to provide material for the eggshells, or the hens will be liable to lay soft-shelled eggs. Burnt oyster-shells are an excellent substitute for common lime, and should be prepared for use by being heated red-hot, and when cold broken into small pieces with the fingers, but not powdered. Some give chopped or ground bones, or a lump of chalky marl. Eggshells roughly crushed are also good, and are greedily devoured by the hens.
A good supply of gravel is also essential, the small stones which the fowls swallow being necessary to enable them to digest their hard food. Fowls swallow all grain whole, their bills not being adapted for crushing it like the teeth of the rabbit or the horse, and it is prepared for digestion by the action of a strong and muscular gizzard, lined with a tough leathery membrane, which forms a remarkable peculiarity in the internal structure of fowls and turkeys. "By the action," says Mr. W. H. L. Martin, "of the two thick muscular sides of this gizzard on each other, the seeds and grains swallowed (and previously macerated in the crop, and there softened by a peculiar secretion oozing from glandular pores) are ground up, or triturated in order that their due digestion may take place. It is a remarkable fact that these birds are in the habit of swallowing small pebbles, bits of gravel, and similar substances, which it would seem are essential to their health. The definite use of these substances, which are certainly ground down by the mill-like action of the gizzard, has been a matter of difference among various physiologists, and many experiments, with a view to elucidate the subject, have been undertaken. It was sufficiently proved by Spallanzani that the digestive fluid was incapable of dissolving grains of barley, &c., in their unbruised state; and this he ascertained by filling small hollow and perforated balls and tubes of metal or glass with grain, and causing them to be swallowed by turkeys and other fowls; when examined, after twenty-four and forty-eight hours, the grains were found to be unaffected by the gastric fluid; but when he filled similar balls and tubes with bruised grains, and caused them to be swallowed, he found, after a lapse of the same number of hours, that they were more or less dissolved by the action of the gastric juice. In other experiments, he found that metallic tubes introduced into the gizzard of common fowls and turkeys, were bruised, crushed, and distorted, and even that sharp-cutting instruments were broken up into blunt fragments without having produced the slightest injury to the gizzard. But these experiments go rather to prove the extraordinary force and grinding powers of the gizzard, than to throw light upon the positive use of the pebbles swallowed; which, after all, Spallanzani thought were swallowed without any definite object, but from mere stupidity. Blumenbach and Dr. Bostock aver that fowls, however well supplied with food, grow lean without them, and to this we can bear our own testimony. Yet the question, what is their precise effect? remains to be answered. Boerhave thought it probable that they might act as absorbents to superabundant acid; others have regarded them as irritants or stimulants to digestion; and Borelli supposed that they might really contribute some degree of nutriment."
Sir Everard Home, in his "Comparative Anatomy," says: "When the external form of this organ is first attentively examined, viewing that side which is anterior in the living bird, and on which the two bellies of the muscle and middle are more distinct, there being no other part to obstruct the view, the belly of the muscle on the left side is seen to be larger than on the right. This appears, on reflection, to be of great advantage in producing the necessary motion; for if the two muscles were of equal strength, they must keep a greater degree of exertion than is necessary; while, in the present case, the principal effect is produced by that of the left side, and a smaller force is used by that on the right to bring the parts back again. The two bellies of the muscle, by their alternate action, produce two effects—the one a constant friction on the contents of the cavity; the other, a pressure on them. This last arises from a swelling of the muscle inwards, which readily explains all the instances which have been given by Spallanzani and others, of the force of the gizzard upon substances introduced into it—a force which is found by their experiments always to act in an oblique direction. The internal cavity, when opened in this distended state, is found to be of an oval form, the long diameter being in the line of the body; its capacity nearly equal to the size of a pullet's egg; and on the sides there are ridges in their horny coat (lining membrane) in the long direction of the oval. When the horny coat is examined in its internal structure, the fibres of which it is formed are not found in a direction perpendicular to the ligamentous substance behind it; but in the upper portion of the cavity it is obliquely upwards. From this form of cavity it is evident that no part of the sides is ever intended to be brought in contact, and that the food is triturated by being mixed with hard bodies, and acted on by the powerful muscles which form the gizzard."
The experiments of Spallanzani show that the muscular action of the gizzard is equally powerful whether the small stones are present or not; and that they are not at all necessary to the trituration of the firmest food, or the hardest foreign substances; but it is also quite clear that when these small stones are put in motion by the muscles of the gizzard they assist in crushing the grain, and at the same time prevent it from consolidating into a thick, heavy, compacted mass, which would take a far longer time in undergoing the digestive process than when separated and intermingled with the pebbles.