Ok... so I had an entire tub of momma rat and (I believe) four week old litter die. For presumably no reason.

Here's what I found when I went to check their water this morning:



Here's another, I only have my cellphone right now, terrible image quality..



Here's the situation:

I have smaller nursing tubs for nursing mommas and large breeding tubs where there is either 1.1 or 1.2 rats at all times. I have two breeding tubs and 5~ nursing tubs, as well as a grow-out/larger cage for mommas with large litters.

They are all in my large downstairs room, which is cross ventilated by my basement (when that door is open) and windows/slider to the outdoors. these are only open when it is warm, which it has been, but last night we had a sudden and unexpected cold snap which dropped that room to 55-60~ degrees because a window was accidentally left open. (it's warmer now, I have a heater running the second I woke up and realized how chilly it was)

I feed Mazuri breeder 6F food and give them all tap water, which is changed daily for mommas and every 2-3 days for the breeder tubs. I give them food every day to make sure they always have some and treats at least every two (granola, yogurt covered raisins, yogurt treats). They're bedding is a mix of pine pellets (equine pine, I believe. It's kiln-dried pine (which kills the oils) used commonly for horse bedding) and carefresh. The tub that passed was entirely on carefresh.

ALL of my rats get the same treatment. Same food, same everything.

This tub was underneath another tub (I stack momma tubs in 2's) and the tub above was perfectly fine. They seemed a little freaked, but were totally okay. It got cold, but everyone felt as if they were still warm enough to be alright.

The ONLY thing different that happened to the tub that passed was yesterday morning I found out that a handful of the babies had chewed out of their zips and escaped. My first chew-out and escape. The room they are in is mostly empty, and they is NO poisons or anything they could have gotten into. I scoured the room for any sign on ANYTHING and I couldn't find a thing..

I do not believe it was rat poison, because it makes rats so thirsty they essentially die from over-drinking... but their water bottle was fully functioning and 2/3 full. Only half of the babies had gotten out, and were all accounted for and put back in, so if say only half had died it might have made sense, but ALL of them were dead.

They look like just fell asleep and didn't wake up... :C

All my other rats are okay, so I don't think it was airborne (pleasepleasepleaseno) and I have NO IDEA what it was! I am freaked out and scared for my other ratties, and so upset because the momma that passed was one of my best moms and the sweetest girl..

Could it have been the cold? The escape?? I have no idea..