This is definitely a major issue. They spawn as reinforcements for aggroed zombie pigmen. I´ve did some test runs and saw them spawn... actually quite frequently when there are aggroed ZP around... tested it with Iron Golems. then my best guesstimate would be that for every 80 or so ZP a regular zombie will spawn, spawning extras subsequently when attacked.
Joris van Veghel
This is definitely a major issue. They spawn as reinforcements for aggroed zombie pigmen. I´ve did some test runs and saw them spawn... actually quite frequently when there are aggroed ZP around... tested it with Iron Golems. then my best guesstimate would be that for every 80 or so ZP a regular zombie will spawn, spawning extras subsequently when attacked.