Well, firstly none of her remarks indicate that she is unwilling to have children EVER, just that at present her animals are her ‘babies’, which of course could change in future.
Neither, from what you’ve said, is there anything indicating that they are DELIBERATELY choosing not to have children - for example using artificial birth control. Perhaps one or both is simply naturally infertile?
Finally, even if they ARE childless by deliberate choice, there may be perfectly valid reasons. It is perfectly acceptable not to have children if they would be an overwhelming burden on the health or finances (and these days even a lot of animals probably cost less than a child when you factor in costs of education and such). As long, of course, as one uses natural means like NFP or abstinence and not artificial birth control.
Short answer - there could be much more going on behind this childlessness than you know or need to know about, so don’t go assuming the worst.