Mishnayos Uktzin Perek 3 Mishnah 3

נבלת בהמה טמאה בכל מקום – whether in the villages or whether in the marketplaces.

צריכין מחשבה – for undefined they are not for consumption.

ואינן צריכין הכשר (and they don’t require preparation) – neither preparation of water nor preparation of a creeping animal/insect [for susceptibility to ritual defilement], for there is no need to have something impure to touch them to defile them, for ultimately they will be impure on their own a grave defilement. And if you should say, it is all right that the carron of a pure/clean fowl and it doesn’t defile other than in the esophagus, it is satisfactory that it requires intention to defile a light defilement. But the carrion of a beast that defiles through contact and through lifting, why do I need intention, for a light defilement, it is an impure body. This manner is answered in the Gemara in the chapter דם שחיטה/The Blood of Slaughter (Chapter 5, Tractate Keritot, folio 21a), as for example, that there is less than an olive’s bulk of carrion, and he attached it to less than an egg’s bulk of food, for whether this one or that one’s an egg’s bulk, and for this reason it requires intention. But nevertheless, it is considered ultimately to defile a grave defilement and doesn’t require preparation, for since it was possible to combine it to be an olive’s bulk.

בשווקים – that there is a majority of the people that come to the marketplace, there are many that eat the carrion of a clean fowl, and consume fats.

אינן צריכין לא מחשבה – for they standing for eating.

ולא הכשר – for the carrion of clean fowl ultimately will defile a grave defilement, that will defile clothing in the esophagus, and regarding fat we are speaking of impure fat, that fat defiles like meat, as we learn further on in our chapter (see Mishnah 9), therefore we don’t require preparation.

רבי שמעון אומר אף הגמל וכו' – they (i.e., the carrion of a camel, a rabbit, a hare and a pig) – do not require intention in the marketplaces, for there are many people who consume them, and this is not like the first Tanna/teacher who stated that the carrion of an unclean beast in every place and didn’t exclude these. But the Halakha is not according to Rabbi Shimon.