It says in the Tosefta [מובאת בתוספות חולין י"ב ד"ה שהרי אבדה] that if one's chicken was stolen and he later found it shechted, he may eat it. We assume that even though the person who took it was a thief, he nevertheless was careful about the laws of שחיטה.
The Rambam [שחיטה פ"ד ה"ח] rules that if one LOST his chicken and found it shechted he may eat it under the assumption that it was properly slaughtered. This would imply that if it was stolen then he may NOT eat it - otherwise the Rambam should have told us the BIGGER chiddush that even a גנב's שחיטה is a valid one.
Why did the Rambam stray from the Tosefta [which, for the uninitiated, is a Tannaic source]?
