Very good attempt at adding a toy, try to implement this code: 
    animal = Animal.new(name, age, gender, species)
    print "Would you like to add a toy (y/n)?"
     add_toy = gets.chomp
    while add_toy == "y"
       puts "What toy would you like to add?"
       shelter.animals[name].toys << gets.chomp
       print "Would you like to add a toy (y/n)?"
      add_toy = gets.chomp
    end