I'm not sure there is an exact time limit to leave a rat out, but more of a personal opinion. Define a little longer? I think if you usually do 3 and you accidentally did 5...it's not a big deal. Possibly even overnight (probably not ideal, but probably not unsafe either). I thaw completely differently, so I don't really worry about this. I usually take the rats I need out of the freezer and put them in the fridge overnight, then about 20 minutes before feeding I put them in hot water.
A bp will know the difference between a "good" rat and a "bad" rat, unless of course it's a garbage disposal like my normal, he'll eat anything. I've had a rat that I thaw out and every single one of my bps refuse and it looks normal, but it's probably bad somehow so they definitely know the difference.
Reply With Quote