I am having this problem a lot more often lately, I heard of it from others but I see it now in my own roos too.

When a roo eats, they age a quarter day, which means you get a shorter breeding span on your roo and they get out of sync with their breeding partners. Not cool.

http://www.worldofmeeroos.com/meeroos/meeroo/2892042

http://www.worldofmeeroos.com/meeroos/meeroo/2883605

Born within seconds of each other, but yet Penelope is a quarter day older than Odysseus now.