Try fixing up your diet before considering supps. You're still fairly young. A lot of potential for growth even without supps. For now

If I'm not wrong he meant one whole chicken or two. Not one or two pieces of chicken.

try to go for the lean body parts, chicken breasts.

It's not just chicken. you can get lean steaks, turkeys. etc etc.

try not to depend on supplementation too much at your age. You're still very young and you have a lot of room to grow before the need for supplementation.
As the word meant, supplementation, is to supplement what you're lacking, not to replace.

so,

EAT