At first it is hard to tell. Within about 3 weeks you should feel a little swelling in the abdomen. She should be eating more, drinking more. You should be able to definitely tell by 6 weeks and possibly even feel movement. She will become more and more shaped like an eggplant is she is pregnant, wider in back and sides. If there is a possibility of pregnancy I would move her to a cage of her own as she can get reimpregnated within a couple of hours of delievery .Also is there is any chance of pregnancy make sure you provide fresh water, premium pellets daily along with veggies such as greens, broccoli, carrots, daily . Very small amounts of mild apples and oranges once or twice a week. Also provide plenty of timothy and/or alphapha hay daily , as much as she can eat. During pregnancy I do a mixure of timothy, and alphapha as alphapha provide extra calcium but I do not ever feed alphapha unless it si to the babies, pregnant or lactating moms as it can cause problems.