If this is a complex issue to resolve, I suggest a simpler work around for the time being:
Don't let zombies pick up eggs
You'll still end up over time with an entity count problem for chickens, but the chicken jockey spawn rate should be much lower than the regular zombie spawn rate.
If this is a complex issue to resolve, I suggest a simpler work around for the time being:
You'll still end up over time with an entity count problem for chickens, but the chicken jockey spawn rate should be much lower than the regular zombie spawn rate.