First of all, animals should not be used for work because :im-vegan: . But having said that... I see how human labor creates surplus value. And I think I understand why machines don't create surplus value. But what about animals that get exploited to perform work, say the mule that pulls a plow? Like humans, they require a "real wage" to sustain them i.e. food, shelter, and medical attention, right? And if the value of labor power of a day of a mule is say 2 hours (that's how much human labor is invovlved in making feed, etc), then if this mule works for more than 2 hours, are they not creating surplus value for the capitalist that claims to own them?
Domestic honeybees make more honey than they need, and hives in human care are protected from predation allowing the hive to continue to surplus honey. Why on earth would a bee keeper take so much honey that the hive can't survive the winter?? Bees are some of the least exploited agricultural animals, if a hive isn't happy they can just leave.
They actually can't leave, the queens wings are often clipped. Or the queen is kept in the hive away from the honey with a "queen excluder " mesh