I have a feeling she boards her horses at cheap, low-end places with cheap, low-end labor, and maybe she pays them for a month or so but then stops paying. So after months and months of not getting paid, they cut the horse’s feed down to next to nothing - and yeah, there are places like that owned and/or managed by low-end people whose main concern is spending money on other things (hint-hint), rather than on providing adequate care for animals in their charge.
Or she puts them in a rough board situation and pays someone on the side to feed them but orders the person to give then only a few flakes of hay each day. Because you know, proper feed and hay for a broodmare costs $$$$ and she certainly isn’t going to spend her money on keeping a cheap-ass recipient mare in good condition (being not only uncaring of the toll malnutrition takes on a pregnant or lactating mare, but also completely ignorant about the toll malnutrition takes on a developing fetus or nursing foal).
And then when she gets outed for starving her mares and foals, she blames “the help.” What a cockroach…