I hunt as often as I can; from small to large game my freezer is always stocked. For the smaller critters, these are some of the guidelines I try to follow:
If it is only a day old it will be good if the temperatures are not to hot. Being from Canada it usually doesn’t get that hot except the dead of summer.
Severe bloating of the carcass may indicate trouble. As well as a lot of flies.
Obvious signs of sickness (foam around the mouth) etc and I would not chance it.
The best advice is never to handle any game without good, strong latex gloves. The best indication that the meat has turned will be the smell when you cut into the flesh. The innards will stink anyway, but isolate a piece of the red meat, get close and give it a good smell. Trust me, if the meat is bad you will know.
If you ever have ANY doubts as to the quality don’t take a chance on it.
It is best to check any traps in the early morning before the sun gets too high. any game caught should be still safe to eat. My advice is to check often so nothing will sit in a trap too long.
a lot of animals carry parasites etc, but when cooked properly it will be safe to eat. Try to avoid cross contamination and ensure to wash your knife very well before cutting anything else you may put in your mouth.
If using a deadfall trap, do not put so much weight as to totally crush to prey. If broken ribs puncture the innards (especially the stomach) then chances are that your kill will be no good to eat come morning. Ruptured guts ruin meat very fast, so even if you do it by accident while cleaning wash the goop off as quickly as possible. It’s Nice to have a water supply handy to wash to old blood and stuff off anyway, as this will keep the meat fresh on the trip home. On really hot days, a few disposable ice packs placed into your game bag with your critters will keep them nice and cool.
Hope this was some help.