When I went to retire one of my wolves, a defect one that had extra toes, for getting space in the pack, some how my wolf with the boost crushing strength got retired instead. I'm not sure if this is a bug or not but on my other account -Firewolf- I lost my chemira defect wolf to the same then, though with that one I had tried to reset her breeding count and tried to use a Fertility Figurine.

how old were they? and when did this happen

The one with Crushing strenth was only a pup, the wolf with extra toes was either a pup or 2 years old, I cant remember the exact age. this had happend near the end of last month

you may have hit retire if they were young the others if they were 15+ maybe died Monday

Maybe you were on the wrong wolf page?