A/an or the.he changes sheep for goose. he changes goose for hen. he changes for apples.the old man brings apples to his wife. he gets some money from .

He changes the sheep for a goose. He changes the goose for a hen. He changes the hen for apples. The old man brings the apples to his wife. He gets some money from an Englishman.
В тексте нет конкретики - поэтому возможны варианты использования артиклей.