Chinchillas with heart murmurs do need special attention. A heart problem is never something to shrug off. They need gentle handling, good supplements, shorter play periods and should never become a parent. Males can become a little to excited ... enough said on that. The strain on the body for a female chinchilla to carry, develop, deliver and raise a litter can often be just to much for a chinchilla with a heart murmur to survive. I always advise breeders, chinchilla owners, to have the chins checked out before putting them into breeding. The more irresponsible breeding of chinchillas with heart murmurs would definitely make it a "common thing" for chinchillas to have heart murmurs and could be the beginning of the end for all chinchillas. Keep in mind ... anytime you place two chinchillas of the opposite sex together ... even for a minute or so ... the possibility of pregnancy is always there ... Please, be a responsible breeder!
Most of the time, a good breeder will be able to tell the difference ... most pet store employees have little knowledge and find out first if you want a male or a female before they tell you the sex of the chinchilla.
What could be wrong with this? Maybe they are to embarrassed that they do not know the difference OR they want the sale, regardless of the sex of the chin.
It is sometimes confusing at birth, because they are so tiny, but by the time the chin is old enough to be weened/adopted, it should be obvious. Check the pictures of the kits below ... these kits are less than a week old.
Note that I am lifting the tail from behind and above, rather than just turning the kit over in my hand. Raising the tail makes it easier to tell ... I think. Click on each picture to enlarge them.
Hope this helps!
Jo Ann