2,588. A Presumption of Health

Hilchos Shechita 11:2

While waiting to determine if a doubtfully treif animal remains intact, it is prohibited to sell it to a non-Jew out of concern that he might sell it to a Jew.

Hilchos Shechita 11:3

We assume that all domesticated and wild animals and birds are healthy; we don’t suspect that they might be suffering from one of the conditions that would make them treifos. Accordingly, when slaughtered properly, they need not be examined for such conditions. Rather, we assume them to be permitted unless something happens that gives us reason to suspect otherwise. If that happens, we only inspect the animal vis-à-vis that one condition.