Tumors are quite common in an older hen’s reproductive organs. This is an area that hasn’t really undergone a great deal of research and because of this, there is little I can say about this, other than they do exist in all kinds of poultry and can be a common cause of death in an older bird.
Most of the studies that we have found have been done for commercial reasons and therefore consider laying hens that are up to 18 months old or on broilers that are fast growing and slaughtered after 40 days or so. Only a few causes of tumors are known such as Marek’s Disease and Lymphoid Leukosis. If a hen has a tumour, you can expect to see a reduced egg production and eventually death. There isn’t anything that can be done as far as we are aware, other than making her comfortable and considering having her put to sleep if she is suffering.