A fox caught the night before will chew his leg off before you get there in the afternoon or evening, so yeah, they need to be run in the morning IMO.
This kind of misinformation is what grinds my gears. I have never once had any animal chew its own leg off. I have had fox that were asleep in the trap when I got there, they couldn't be more relaxed.
Animals chew on feet not to escape the trap, they do it because their feet go numb. If you use the correct sized trap they don't even have room to chew on their feet anyways.
To say my post is "misinformation" just because you've never seen it is wrong. Perhaps you should ask about a man's experience before jumping to your own conclusions and telling him he's incorrect.
I've trapped for approximately 36 years and in this time I've seen it probably a half-dozen times; it has only been with red fox. I don't know why they do it, perhaps it's like you said, their feet go numb; I don't know.
And like others have posted, I've seen animals asleep when I've come to the set, I've had coyotes and fox held by two toes and I've also seen coyotes (male) that let me know he was going to chew me up if he got the chance.
ETA: I don't know that this makes any difference, but the times that I have seen this, the animal didn't chew his feet off, it was his leg (as I stated in my initial post) just above where the jaws of the trap had him held.
