is it legal to casually raise money for a good cause and advertise it?

[Jake]

You could more easily publicize the charity, but advice people to pay the charity directly, the possibility of you fraudulently collecting money for your own gain, (like the out of town people selling candy outside of the stores) is the biggest legal issue as well as putting people off from donating.
Just actively raising public awareness of the plight of animals, like a political campainer would also help your cause in a more indirect way.