Assume a chicken costs an integer number of cents.

Then x42y is divisible by 8 and 11. y must be even, and we can use the test for divisibility by 11 using digits: x - 4 + 2 - y is divisible by 11. That is, x - y - 2 is divisible by 11. It can be seen that 0 is the only attainable number, so x-y-2=0 and we try

(x,y) = (2,0)

(x,y) = (4,2)

(x,y) = (6,4)

(x,y) = (8,6)

The only one that works is (x,y) = (6,4), so we have $64.24 and each chicken costs 73 cents.