The polish isnt a bantam, but its the size of one. Little smaller than the brown leghorns. I just heard their not cold hardy. We get bellow zero weather here sometimes and my father always had a few bantams with his RIReds, they never got cold, sick, or anything. I never even heard of worming chickens until reading threads on this site, Im still a little iffy on that, my father never wormed his, never any problems. But that was 25-30 yrs ago. Actually he always had around 30 usualy, plus little ones and none of them ever died, only by axe, until a weasel visited them and he lost almost all of them in two nights.