Although the lump under the skin of a bird's neck looks like a lymph node, it is really not a lymph node but a thymus gland. There are very few lymph nodes in poultry (chickens don't have them at all, ducks and geese have a little bit). This is different from mammals. As for lymph nodes, lymph nodes are peripheral immune organs, which are the main places for immune response. Residual pathogens and other substances ingested by organisms that need to be delivered to the immune system may be enriched in lymph nodes. There is a risk that food such as steamed stuffed buns, in which meat is mashed, will be mixed into this stuff by illegal traders.

Thymus may contain more germs and viruses and should not be eaten. In addition, thyroid gland and parathyroid gland contain more hormones and should also be avoided. In the standard slaughter, these glands and trachea will be removed, so the necks of chickens and ducks bought from regular channels should not have these parts. As for the rumored "lymph nodes", in fact, there are no lymph nodes in chickens and ducks at all, only lymph aggregates with the same effect.

If there is no lesion, it will not cause obvious harm if it is eaten in a small amount after sufficient heating. The main function of thymus is to induce hematopoietic stem cells to differentiate into mature T cells with no immune function. Under normal circumstances, thymus is not in direct contact with pathogens (and lymph nodes are the main places where immune response occurs), and it is not a metabolic organ like liver and kidney. It seems to have nothing to do with detoxification. However, the function of thymus is regulated by many hormones, and it also secretes thymus stimulation. The difference between thymus and lymph nodes is that although both of them may swell when pathogens invade, thymus is a central immune organ.

Its swelling is only due to the fact that the body mobilizes immature T cells into mature T cells (reactive proliferation), and then transports the mature T cells to peripheral immune organs to play a role, and it will not directly contact with pathogens. Therefore, under normal circumstances, it will not enrich all kinds of toxins.