Nether chickens would be similar to the Cluckshrooms of Minecraft earth, but with a more fiery theme. They would drop gold nuggets like how the regular chicken lays eggs. Piglin/Zombie Pigmen children could ride them like a baby zombie and a normal chicken. It would be passive and be fire-resistant .
Interesting, i think the nether chickens should be extremely fast, and run when a player gets near them. You'll Most likely need a bow and arrow to take it out but if you miss, the chicken will go into attack mode and try to set you on fire