Interestingly enough yesterday's (Shabbos) daf (נזיר כ"ח) discussed both women shaving their heads and wearing sheitels.
There is a din that a husband can annul his wife's vows including a vow of נזירות. The Mishna discuses until what point can he annul the vow and has a dispute between R' Meir (or Rebbi depending on the girsa) whether he can annul the vow after she brings her korbanos but before she shaves her head (a נזיר after he completes his נזירות has to bring a set of korbanos and then has to shave his head). R' Meir says that the husband can annul the vow even after she has brought the korbanos because he can say that he doesn't want his wife to have a shaved head (because he doesn't like it). The Gemara explains that the Tanna Kama disagrees with R' Meir because the wife can wear a wig (פאה נכרית) and the מפרש explains and that it looks like her head isn't shaved and therefore the husband has nothing to object to. R' Meir says that the husband can object to a wig that he doesn't like it.
Form this Gemara we see a number of very important points regarding both shaved heads and sheitels:
2. The Gemara assumes that a woman with a shaved head does not look good and is not pleasing to her husband.
Based on the above I don't see any way to claim that a married woman must shave her head as many Chassidic groups require. In fact, we see just the opposite, that at the time of Chazal married women did not shave their heads and a woman with a shaved head was considered not attractive to her husband.
There is a din that a husband can annul his wife's vows including a vow of נזירות. The Mishna discuses until what point can he annul the vow and has a dispute between R' Meir (or Rebbi depending on the girsa) whether he can annul the vow after she brings her korbanos but before she shaves her head (a נזיר after he completes his נזירות has to bring a set of korbanos and then has to shave his head). R' Meir says that the husband can annul the vow even after she has brought the korbanos because he can say that he doesn't want his wife to have a shaved head (because he doesn't like it). The Gemara explains that the Tanna Kama disagrees with R' Meir because the wife can wear a wig (פאה נכרית) and the מפרש explains and that it looks like her head isn't shaved and therefore the husband has nothing to object to. R' Meir says that the husband can object to a wig that he doesn't like it.
Form this Gemara we see a number of very important points regarding both shaved heads and sheitels:
Shaved Heads
1. It is clear that married women didn't shave their heads, otherwise the husband would have nothing to object to.2. The Gemara assumes that a woman with a shaved head does not look good and is not pleasing to her husband.
Based on the above I don't see any way to claim that a married woman must shave her head as many Chassidic groups require. In fact, we see just the opposite, that at the time of Chazal married women did not shave their heads and a woman with a shaved head was considered not attractive to her husband.