well a chicken has 2 legs so do 2 times however many chickens there are to get the total of chicken legs. a pig has 4 legs so do 4 times however many pigs there are to get the total of pig legs. once u have those answers, do the total of pig legs plus the total of chicken legs to get your total of legs. for the number of heads, do the number of chickens plus the number of pigs.
