Feeding question for my 17 year old corn snake

[Marsbars]

Hello everyone!
I've had my corn snake slinky for 17 years now and hes always been healthy in pretty much every respect. For the last five years we've been feeding him 2 adult mice once a month and I recently noticed that hes been pooping way more than he should. Since he was last fed hes pooped 3 times, most of the time its actual poop versus the urea. I'm worried that maybe we have been over feeding him all these years and wanted to get some opinions.
Thanks!
Mars

[EL Ziggy]

Welcome to the forum Mars. I definitely wouldn't consider one adult mouse bi-weekly or 2 adult mice once a month overfeeding. I'd actually be feeding it a bit more. Please share pics of your mature critter when you can.