A mod called Earth Chickens “ports” chickens to Minecraft Bedrock Edition from the popular Minecraft Earth. Why is there such variety? It’s that simple! There is only one type of chicken in vanilla Minecraft for Android – white, “standard” chicken. Now, with the Earth Chickens mod, there will be more varieties in Minecraft BE.
There are no special advantages in Minecraft Pocket Edition mod. Think of it as a “cosmetic” mod that targets a variety of mobs. Which, by the way, is almost completely absent in MCBE. The mod works in MCPE on version 1.16. Have a good game!