Two of our chickens, (a polish top hat, age 7, and a wyandotte, age 5), have been throwing up clear liquid every now and then. Our polish top hat has been throwing up for around 5 months but we’ve only seen it happen about 10 times. Our wyandotte has been throwing up for around 3 months and we’ve only seen it about 7 times. We can’t constantly watch them so it’s hard to tell how much they do it and when they do it. However, they still act like they’re heathy. They still lay eggs, eat, drink, etc. Are they sick or this old age?