How to say extra chicken in Thai?
Many times I go out to eat but usually the portions are small in Thailand. I am much bigger than the Thai people so I need to eat more 5555 How can I ask for extra chicken? I say sawatdee krap, kow pat gai 1 jaan gap (extra) gai?

Please tell me in Thai language. I can read it.

Question

How to say extra chicken in Thai?
Many times I go out to eat but usually the portions are small in Thailand. I am much bigger than the Thai people so I need to eat more 5555 How can I ask for extra chicken? I say sawatdee krap, kow pat gai 1 jaan gap (extra) gai?

Please tell me in Thai language. I can read it.

Answer

สวัสดีครับ ข้าวผัดไก่ 1 จาน ขอไก่เยอะๆนะครับ 
(ขอไก่เยอะๆ its mean Extra chicken too :)

Answer

You can say .ขอไก่เพิ่มด้วยครับ  
เพิ่ม and พิเศษ  in your case are the same meaning ka^^

Answer

you can just say "ขอไก่เพิ่มได้ไหมครับ ?"

Answer

it's not too different in this situation.
but actually the both meaning is different. 
 พิเศษ means special, extra, not normal
 special friend = เพื่อนที่พิเศษ

เพิ่ม means to add, to increase
add friend (face book) = เพิ่มเพื่อน

sorry if i can't explain you as crystal clear but i hope you get it.

Answer

You are amazing. What's the difference between  เพิ่ม and พิเศษ