I have 10 Silkie eggs in my incubator on day 18 today. One already started to internally pip yesterday. I noticed something while doing one last candle check up before lockdown, which i have never seen before during hatching when i candled yesterday. I saw the chicks head and beak on one side in the air pocket, but on the other side i noticed another dark bump, which looked to be moving seperately. At one point the bump with the beak moved very slow, but the other bump moved very active. I am almost afraid they might be twins, even though the changes are very odd. Is there a way to be sure? Maybe weight the egg?