I've always had that spell function very similiarly to astral construct.... Or to say, these creatures aren't creatures that exist elsewhere and come to your aid, but that they are constructed by magic, take the form of the animals in question, along with certain basic functions, but they aren't real... at the end they don't go away or return anywhere if alive, instead they simply evaporate... redispersed into the ether, lose their form and function as the magic that holds them together dissipates.
Thereby neatly avoiding any moral conflicts of using the creatures.