just get them to write in your lease that your allowed small pets and whatever other animal (provided they said u where allowed) and then they cant kick you out as you can bring them to court as it is a written contract there is no specifics as to what small pet you can have.
Actually, not necessarily so...the laws that cover animals and rental leases vary by province/state, and in most cases, contracts must be specific to avoid legal issues. That being said, whatever you do, do not lie about what animals you have (omission/vagueness is fine, so long as you are not asked specifically).
Believe you me, better safe than sorry....a 48 hour eviction notice with nowhere to move is often a nightmare and then some.