Did prehistoric chickens have sabertoothed beaks?

Well.... There weren't any prehistoric "chickens". The modern-day chicken is the result of the domesticization of various species of wild "fowl" like the guinea hen and similar species. This would have occurred within historic times as a result of breeding for the desired characteristics, much as with all contemporary domestic animals.

However, the fossils of very early birds and transitional bird/reptile species do indeed have beaks which include both teeth and serrations.

Haven't you seen Ice Age? The dodos have normal beaks.

ROTFLMAO. I HOPE NOT although we’ve not found any fossils. That’s a funny thought

I hope so... that would be so cool!