- Objective. Animal models of spontaneous ovarian cancer are important for understanding early tumor development. Ovarian imaging may play an important role in following changes in tumor development. Laying hens are the only animals that develop spontaneous ovarian cancer similar to humans. The aim of this study was to determine the feasibility of detecting ovarian tumors in laying hens using sonography. Methods. Ovaries of commercial strains of White Leghorn laying hens (n = 29, 2.5‐3.0 years old) were examined by transvaginal 2-dimensional gray scale and color Doppler sonography. Sonographic evaluations were compared with ovarian anatomy and histologic features. Results. Results of in vivo sonography and ovarian anatomic and histologic examinations were consistent. The presence of gross ovarian tumors was correctly detected in all hens by sonography. The resistive and pulsatility index values associated with ovarian tumors were lower than for normal ovaries (P < .001) suggesting that blood flow velocity was increased in ovarian tumors. Values associated with abnormal ovarian histologic findings but no gross tumors were intermediate. Conclusions. Transvaginal sonography can be used to determine ovarian status in hens. It offers the ability to make repeated examinations on the same hen to monitor early changes in the ovary associated with ovarian cancer. Key words: animal model; laying hen; ovarian cancer; sonography.