Round 1: 1+24 is only infected [1 to the power of (1+24)]

The second round: the quadratic of (1+24) * 24+(1+24) = (1+24) only infects (the common factor is extracted from (1+24)).

Round 3: the second power of (1+24) times 24+( 1+24) = infection only (the common factor is extracted from the second power of (1+24)).

Note: Add infected chickens.