fodder vs hay

fodder and hay both are nouns.

Word	Noun	Adjective	Verb	Adverb
fodder	Yes	No	Yes	No
hay	Yes	No	Yes	No

As nouns, hay is a hyponym of fodder; that is, hay is a word with a more specific, narrower meaning than fodder:

fodder: coarse food (especially for livestock) composed of entire plants or the leaves and stalks of a cereal crop
hay: grass mowed and cured for use as fodder

Other hyponyms of fodder include eatage, forage, grass, pasturage, pasture, alfalfa, broad bean, horse bean, stover.

fodder (noun)	hay (noun)
coarse food (especially for livestock) composed of entire plants or the leaves and stalks of a cereal crop	grass mowed and cured for use as fodder
soldiers who are regarded as expendable in the face of artillery fire

fodder (verb)	hay (verb)
give fodder (to domesticated animals)	convert (plant material) into hay