In South Africa ostriches graze in the veld, and it is just not possible "to ensure that potential foreign objects are removed". Ostriches do not just die after having eaten a few nails; surely this is proven by the fact that some that were imported already had nails in their stomachs.
According to the Standard Encyclopaedia of Southern Africa, "the ostrich is a bird of arid, semi-desert country". My guess is that the ostriches over here died of home-sickness.
A van Antwerpen
AS A regular reader of Big Eggo in The Beano many years ago, I took it for granted that any nut, bolt or flywheel missing at a critical moment, would have been eaten by an ostrich and any doubts were dispelled by pictures of the object outlined within the animal's gullet on the way down. No bird able to swallow the entire exhaust system of a Ford Popular as easily as an oyster would even hiccup over a few metres of barbed wire. Magnets - as I remember - usually put things right.