How could they?
Why would they?
As for keeping pets for profit they are not given to raise pets for such. That's even not proper for a lay person wishing for Brahmacariya and Uposatha Sila.
As for feeding intentional and personal pets with alms, monks are not even allowed to give to lay people.
Why would they? They do out of affection, lust and in association with low.
If seeing a monk keeping pets, such is lower as to keep children, such is lower as to share the gifts out of faith to ordinary people, such is given alms dedicated to Noble Ones to beings without virtue intentionally.
If seeing a monk stroke pets or enjoying touch of pets, or delight in the behavior of pets, be sure that he is far from Brahmacariya. He simple feeds for some degrees of lust and sex.
And having done so, who cares of the animal when he walks on? Or how could he walk on, if he is by defilement bound to care?
People living in association with pets, while avoiding humans, are known that they have grave social disorders. It's just another sexual, lust, perversion.
And if not falling into the told, they keep pets to make lay-people a favor and cause affection, are on the road of corrupting families and to be seen near Sanghadisesa 13.
And if having even ideas of "my pet" they are simple blind fools.
As for association: It's not to be expected, that one who associate with animals has good ways to grow in Sila, generosity, concentration and wisdom.
Equal meets each other again and again, tend to each other again and again, and nourishes each other.
See also:
Association with pets - Associated rebith? Btw.: association and living, and keeping and feeding people in Dhammic centers who are not capable to grow in Dhamma (without Sila, Dana,...), isn't different to someone feeding and keeping pets. It's simply desire for sensuality and becoming and Abrahmacariya that drives one to be a pet keeper monk. For his gains and to nourish on them, having feed them and make them dependent on one.