The first symbol is hard to understand at first, I feel like it's only successful with text explaining it is a fish. Also, maybe a blue background would make the understanding more clear.
I believe this image of apples is a strong symbol because the apples are easily understood as apples they are not photorealistic, but rendered in a quick stroke style.
The illustration of the chicken is easy to understand, has the colors recognizable with a chicken, and also shows a egg making one think of chickens which is why I feel this is a successful symbol.
