I'm seriously stuck on Level 51!! Can somebody PLEASE provide me with s…

I'm seriously stuck on Level 51!! Can somebody PLEASE provide me with some tips? I've tried everything. I've used everybody's advice like only give rainbow parrots to people with a question mark above their heads, don't give out extras unless asked for and be as FAST as possible. and somebody even told me if you have the machine that cleans up animal foot prints don't worry about putting them back into their cage, focus on the customers. Any tips are appreciated.