Questions & Answers about Isännän on ruokittava kani ja hanhi.
Why is "the farmer" in the genitive case (isännän) instead of the basic nominative (isäntä)?
This sentence uses a necessity structure to express that someone "must" do something. In Finnish necessity structures, the person who has to perform the action (the subject) is always put in the genitive case.
What is the grammatical structure of on ruokittava?
It combines the verb olla (to be) with the passive present participle of ruokkia (to feed). The -ttava / -tava ending creates an adjective-like word meaning "to be fed". Together with on, this structure is a slightly formal way of saying "must feed" or "has to feed".
Why are the objects kani and hanhi in their basic nominative forms instead of taking the object -n ending?
This is a major rule for necessity structures! While a total object normally takes the genitive-like -n ending (as in Hän ruokkii kanin), when you use a necessity structure like on ruokittava, täytyy, or pitää, the total object drops the -n and stays in the nominative case.
Could I just use täytyy or pitää for this sentence instead?