Ostrich Struthio camelus

The ostrich is the largest living bird and the only ratite farmed at real commercial scale, held in breeding pairs or trios and sold for three products at once: a lean red meat, a distinctive hide and feathers. Hens lay between forty and a hundred eggs a season depending on strain and on which source you read, the eggs hatch after about forty-two days, and birds are slaughtered at ten to fourteen months near 85 kg. Adults run from roughly 90 kg in hens to 130 kg in cocks, and breeding females can stay fertile for thirty to forty years. Veterinarily the ostrich is not a large chicken. It has no true crop, its caeca and colon make up two-thirds of the digestive tract, and it ferments fibre in the hindgut much as a horse does, digesting around two-thirds of dietary hemicellulose. That capacity only develops near ten weeks of age, which is why chicks given fibrous rations too early suffer gastric impaction, reported in thirty to forty-six percent of birds in the first six months, alongside calcium and phosphorus related leg deformities. Newcastle disease has killed eighty percent of three to six-month-old birds.