Due to the min-max capabilities of the chicken, your strength, constitution, and intelligence fall 1 in exchange for an increase in dexterity and wisdom. Hope you're using point buy.

Not even common. Due to this, "chicken" is now a language. It sounds like a chicken. Background languages should be disregarded. Characters that spend immense amounts of time with you may start to understand some of what you are saying, similar to Han Solo and Chewie or Rocket and Groot. Yes, you can still cast spells.

You gain +3 extra on passive perception and skills in choice of Athletics, Nature, Stealth, or Survival. Pick 2. In addition to those, you get an extra skill in perception, since chickens have really good eyes. Look it up sometime. Also, to those wondering, no, they don't have good vision at night. That's why no darkvision.

Anything that you really think could be carried in your beak is allowed, and other things may be able to be carried on your back if someone makes you some kind of special saddle or something.

Your beak is a consistent source of damage, considering it can't be removed. It deals 1d6 of piercing damage and is a simple weapon in relation to classes.

This is a chicken exclusive spell. Don't get your hopes up. It is a control cantrip that makes ALL creatures in a 10 foot raidius make a constitution saving throw against 10 plus your strength modifier. If they win, they are unaffected, if not they move their speed away from you. Anyone who is deaf is automatically unaffected, and females do not have this option.