INFLUENCE OF DIET UPON COCCIDIOSIS IN CHICKENS    349

       Previous to the introduction of the confined brooder-house there had been
definite loss from coccidiosis among the young chicks in the late summer and
autumn hatchings.

       In 1931 a change was made in the feeding of certain of the chicks. These
were given a ration which was calculated to supply growth and maintenance
requirements but not fat, in other words a store ration. This was fed for the first
time to a batch of 100 chicks. These chicks commenced to die at the end of the
third week, and by the end of the sixth week the majority were dead and the
survivors were unthrifty and worthless. One or two of the dead chicks were sent
to the Ministry's laboratory at Weybridge and a diagnosis of coccidiosis was
returned. Meantime other chicks kept under comparable conditions, but receiving
the customary ration fed at the Institute continued to behave apparently normally,
and though a number of these animals died, they were too few to excite suspicion,
and the cause of these deaths was not ascertained. At first it was thought that the
chicks fed upon the store ration and which died from coccidiosis must have been
accidentally exposed to a heavy infection, and fresh houses were selected which had
been free from all poultry for a period of twelve months, and into these houses
batches of newly-hatched chickens were placed. These were again fed the two
rations in order to test their relative merits as regards growth in the chicks, etc.,
but again the experiment was upset in as dramatic a manner as on the former
occasion, chicks fed on the store ration rapidly dying while the others survived.

       The results of feeding this store ration were so striking, though along an entirely
different line from that intended at the commencement of the experiment, that it
was considered of sufficient interest to follow the course indicated and ascertain as
far as possible if the ration alone did play such a vital part in the incidence of the
disease. Accordingly, with the supervision of the Veterinary Department of the
South-Eastern Agricultural College, a further experiment was planned under
what appeared more controlled but still farming conditions. The plan of the
experiment was as follows:—Six hover houses and sun parlours were selected. In
none of these had there ever been chickens with a known history of coccidiosis.
These houses were grouped in pairs. One pair was scrubbed out, disinfected, and
sterilised as far as possible with a blow lamp. The second pair was scrubbed out
and disinfected only. The last pair was scrubbed, disinfected and blow-lamped,
and then infected with coccidia by spreading a mixture of droppings of infected
chicks equally upon the floors and brushing these out after 24 hours.

       Into each prepared house 94 chicks all from one hatching were placed. The
chicks in one house of each pair were fed upon the store ration, those in the
remaining three houses were fed the institute ration. The results which followed

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