answer:This suggests a number of possibilities. Simplest and most reasonable, is that Lucy came into contact with something that had the scent of her heat on it, maybe where she had brushed up against some furniture, or a door or something. The scent transfer would be enough to make the boys react. A much more complex possibility is if she has been switched to a grain free diet recently. Some of them have legume fillers (soy, some peas or beans) that are high in phytoestrogens that can wreak havoc with normal hormone levels. Unlikely but possible. A friend who is a hobby breeder had such issues while her dogs were on grain free food. There you go, from basic to complex possibilities. :-)