It could be. It's really hard to tell with out pictures. How many locks have you seen? How long have you been pairing? Have you palpated her? If you're afraid of palpating, handle her for a bit and once she relaxes, put a snake bag or pillow case on your hand and slide your hand down her underside. If she's close to ovulation, then you'll be able to feel the follicles. Don't be afraid to put some pressure on her belly, she'll just flatten out a bit and it will actually make it easier to feel the follicles and they should feel like big marbles. They're quite unmistakable if she's actually building close to Ovy