Pig might look like a tiny little horse, but she isn't, so he's likely to be in for an unpleasant surprise if he tries to escalate. That being said, it seems she'll consider the question seriously, before she finally responds.

"I don't know. Maybe it's because you already have so much magic of your own. Creation is more about potential than power."

Of course, this is before they learn Rita has been turned into a Guardian too, so...