mixture is shown by some experiments reported later in this bulletin.

2.

MINERAL ELEMENTS SUCH AS CALCIUM (LIME), PHOSPHORUS ETC. These occur to some extent in most plant foods and in almost ideal amount and form in milk. Growing chickens probably need a great deal of calcium, the bone building material, and the practice of adding bone meal or other source of lime to chick rations is an attempt to fill this need.

3. A SUFFICIENT AMOUNT OF ROUGHAGE OR INDIGESTIBLE MATERIAL. The usual sources of roughage are dirt, the fibrous parts of green foods, and other indigestible materials which the chick picks up out-of-doors; shavings, sawdust, straw and other such materials which are generally used as litter; and the fibre which is present in the bran, ground oats, vegetables, etc., which are usually present in the ration. The safest way to insure that chicks reared indoors will receive rather large amounts of inert material is to feed them bulkier, less concentrated rations than to those reared out-of-doors, and to provide plenty of clean litter in the form of shavings, sawdust, etc.

4. SUNLIGHT. It is an important conclusion of recent experiments that direct sunlight and the antirachitic vitamine have similar functions and can to some extent replace one another. Thus chicks receiving an insufficient amount of this vitamine may be successfully reared if exposed to sunlight which does not come through glass. The importance of this for the raiser of indoor chickens lies in the fact that it may be possible to make up for a deficiency in sunlight by adding a sufficient amount of this vitamine to the ration.

Most of these essentials-vitamines, minerals, roughage and sunlight-are supplied usually in sufficient amounts to chicks reared and fed under modern methods with free range out-of-doors. Especial precautions must be taken to insure that indoor chickens shall also receive them.

LEG WEAKNESS

The most common ailment of confined chickens is probably leg-weakness. This condition which unfortunately is

familiar to most poultrymen who have reared chickens indoors. usually develops when the chickens are from four to eight weeks old. The first evidence of leg-weaknes is usually a slight unsteadiness of gait, the affected birds often teetering from side to side in an effort to keep their balance as they walk. The feathers become ragged and ruffled, the joints swollen, and the shanks frequently pale and shriveled, while the bones are sometimes found to be soft and pliable. unsteadiness increases in some cases into complete absence of nervous control, when the affected bird lies on its side with limbs twitching; while in other cases the birds become inactive and drowsy and remain in a squatting position or lie on their sides for long periods The appetite declines in this stage, and death usually comes suddenly.

The

Leg-weakness has been attributed by poultrymen to a great variety of causes; lack of exercise, too dry scratching space. over feeding, lack of green feed or minerals, etc. There appears to be little doubt now that it is a deficiency disease like rickets and is due generally to an insufficient supply of the anti-rachitic vitamine in the ration, although insufficient roughage and minerals in the diet and absence of direct sunlight are undoubtedly complicating causes. It is known that it can be cured and prevented by the administration of cod liver oil, or by exposure to direct sunlight, provided that sufficient minerals and roughage are available. In this aso, it resembles rickets, and there is a tendency at present to reard leg-weakness as rickets of chickens, although full proof of t's has not been provided. It is at any rate apparent that t same treatment is effective in the case of rickets and leg-weak

ness.

In making up a ration for chicks to be reared indoors, then, especial attention must be paid to the prevention of legweakness. This means that until we know more about the exact mineral, vitamine and roughage requirements of the chick, one should allow a safe margin of these in the ration and as much direct sunlight as it is possible to provide.

The vitamine requirements may be met by feeding milk (skim or whole) and a good chick feed of cereal grains with

either beef scrap, fish scrap or bone meal in a mash with which We fresh cod liver oil has been thoroughly incorporated. have found that leg-weakness does not appear in chicks which receive cod liver oil at the rate of one half of one percent of their ration. If they consume equal amounts of mash and scratch grain as usually fed, a good practice is to add cod liver oil to the mash at the rate of one pound (about one pint) of oil to one hundred pounds of mash. The oil may be poured thinly over the mash and rubbed in thoroughly by hand.

It must be emphasized that the vitamine in cod liver oil which prevents leg-weakness may be impaired by heat, oxidation, ageing and exposure to light, and that the source of the oil should be examined carefully with regard to these factors. We have found that cod liver oil mixed in feed and stored in bottles in a cool, dark place for six months did not prevent legweakness, while natural raw oil stored in unopened bottles in the same place for the same time did prevent leg-weakness. We have as yet no information on the value of cod liver oil which has been mixed with feeds and held under the usual methods of storage. Because of the result described above, however, we have in our work preferred to use mixtures of cod liver oil and feed which have been held not longer than two weeks.

The cod liver oil used should be pure raw oil (not an emulsion) and preferably should have been tested for the presence of the vitamine it is intended to supply. Cod liver oils of this sort are on the market* and the cost of the small amounts needed is not prohibitive. We estimate that the cost per chicken for cod liver oil fed as suggested for the first four weeks is about one cent. In commercial practice it will not usually be necessary to feed cod liver oil after the fourth or fifth week for after this time the chickens can usually be sent out-of-doors and cod liver oil is probably not necessary for chickens on a green range with plenty of sunlight.

In addition to cod liver oil or its equivalent, a sufficient supply of mineral salts (and especially of lime) should be present in the ration. These are present in milk (skim or whole) bone meal, some in meat scraps which usually include

*In experimental work at this station, we have used "Cod Liver Oil Harris" purchased from the Harris Laboratories, Tuckahoe, New York.

some ground bone, green feeds and other natural sources. We have usually preferred to add a cheap inorganic form of calcium to the ration, such as precipitated chalk (calcium car bonate) or powdered limestone in order to insure a sufficient amount. The anti-rachitic vitamine apparently regulates the use of minerals by the chicken and sufficient minerals must be present before the vitamine can do its work.

Roughage may be provided and the danger of over feeding minimized by including a large proportion of bran or other bulky food in the ration. Chopped clover hay, chaff, and shavings are valuable as litter and as roughage. Grit should be provided, either as course sand, or as hard granite, quartz or limestone grits.

EXPERIMENTAL EVIDENCE

In the last few years chicks have been successfully reared in complete confinement indoors through careful adjustment

of the requirements outlined above. A few of these experiments may be cited as evidence for the statements above and to provide information on sample rations on which the poultryman can model his feeding methods.

An experiment carried on at this station last year is of interest in that the commercial feed mixture which has been recommended by this station was used as a basic ration, and the adding or withholding of certain supplements in connection with this ration gave striking contrasts in growth and survival. Four lots of ten White Leghorn chicks each were hatched on May 29, and reared from hatching to nine weeks of age in a basement room lighted by two glass windows. The table top, seven and a half feet in diameter, was divided by galvanized iron strips into four equal quandrants and at the center was placed a small electric hover. (See Fig. 1) The only litter provided was clean coarse sand, and tap water was given as the only drink. The STORRS MASH, consisting of equal parts of bran, standard middlings, corn meal, gluten feed, ground oats and meat scraps formed the basis of the mash feed. To this was added for the first three weeks an equa! weight of bran. For the last six weeks the proportions were Storrs mash 2 parts, bran 1 part. Included in the basic ratio. were one per cent of calcium carbonate, and one half per cent of common salt. The mash, therefore, had the following composition:

Fourth through

Second and

third weeks.

eighth week.