The mechanism which causes calcium loss (and ostopenia and even fractures) in the fetus should be the same in the ferret fetuses as it is in human ones: http://www.fda.gov/Drugs/DrugSafety/DrugSafetyPodcasts/ucm354762.htm This is a newly uncovered problem and is changing the FDA info included with this product. Ferret fetuses who are too low in calcium have been encountered when pregnant females are fed chicks or baby mice (both of which are too low in calcium) or are fed a muscle meat diet which is not supplemented appropriately with needed minerals and other nutrients because many nutrients are too low in muscle meat (and the pregnant females from donating some of her own bone calcium to the fetuses but having a diet too low in it can themselves also develop bone and tooth problems as in humans). Kits who develop to be too low in calcium from similarly unbalanced diets in some areas are nicknamed "swimmer" kits because they are unable to bear their weight on their limbs. As most here know: for a long time Steve and I purposely took in ferrets who were born with deformations as part of our busyness of ferrets (until we could no longer afford to do so given that some of those ferrets needed medical care in the five figures to live reasonably long and happy lives) and when the handicapped ferrets were able to do so we integrated them in with the healthy ferrets though not all could manage that, but despite dealing with multiple types of deformations we did not even hear of this low calcium problem until some breeders went away from feeding at least part of their maternal diet from high quality pre-made commercial foods. Some breeders learned enough to manage a safe diet that way but others did not and the reports began. Sukie (not a vet) Ferrets make the world a game. Recommended ferret health links: http://pets.groups.yahoo.com/group/ferrethealth/ http://ferrethealth.org/archive/ http://www.miamiferret.org/ http://www.ferrethealth.msu.edu/ all ferret topics: http://listserv.ferretmailinglist.org/archives/ferret-search.html "All hail the procrastinators for they shall rule the world tomorrow." (2010, Steve Crandall) A nation is as free as the least within it. [Posted in FML 7810]