Robin, I don't remember. Could have been Terramycin or even might have been Tylan. NN may come on and weigh in here. He's so good, he probably remembers. If it is an egg broken inside her, or maybe even just stuck there, the antibiotic could be imoprtant to fight infection until her body can absorb it. Of course, each case is different, and it is often next to impossible to tell just what is going on from descriptions.