spring chicken vs juvenile

spring chicken and juvenile both are nouns.

Word	Noun	Adjective	Verb	Adverb
spring chicken	Yes	No	No	No
juvenile	Yes	Yes	No	No

As nouns, juvenile is a hypernym of spring chicken; that is, juvenile is a word with a broader meaning than spring chicken:

Other hypernyms of spring chicken include juvenile person.

spring chicken (noun)	juvenile (noun)
a young chicken having tender meat	a young person, not fully developed
a young person (especially a young man or boy)

spring chicken (adjective)	juvenile (adjective)
	of or relating to or characteristic of or appropriate for children or young people
	displaying or suggesting a lack of maturity