"The chicken is good."
Translation:Das Hähnchen ist gut.
normal hen = "das Huhn" or "die Henne"
normal rooster = "der Hahn"
When "Hahn und Huhn" are small, cute, or young they are "das Hähnchen und das Hühnchen".
When they are still babies = "das Küken" (For both sexes)
When you refer to all of them collectively: "Die Hühner"
Once they are dead and considered as foodstuff the rules change: practically everything becomes a "Hähnchen".
In German we use both words interchangeably.
A tiny felt difference is if you cook chicken breast I would refer to as 'Hühnchenbrust' and if you for example have a half chicken from the oven or buy half a chicken (at a shop on the street) you would say 'ein halbes Hähnchen'.