bad mama hen

[janjan1]

I have a hen that only has one chick. It's about 2-3 weeks old and she has already "kicked it to the curb". Attempting to peck it to drive it away and grow up. I think it is alittle to early for her to be doing this. At what age do the hens usually start this? Even tho I have other hens, they hang on to the chicks til they are older.
Thanks
Jan