This Halacha is an excerpt from our Sefer
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Chabura Matzahs-Being involved in the baking process:
It is proper for each individual to be present while his Matzahs are baked. He is to help oversee the process and encourage the workers. [This Halacha created the concept called Chaburah Matzahs, in which a group of people rent the bakery, or are added to the line of current workers, and help bake the Matzahs that they will then take home that day. This, however, should only be done if the participants of the Chabura are familiar with the laws of Matzah baking and are experienced with protocol in a Matzah bakery. Having inexperienced, or ignorant, participants can cause Kashrus issues with the Matzos and be counterproductive to the entire reason of having a Chabura. Accordingly, each Rosh Chabura [head of the Matzah baking group] is to instruct and oversee each participant in all the procedures involved in Matzah baking.]
 Admur 460:3-4; 453:33 regarding grinding; See Avnei Nezer O.C. 372 who wanted to nullify the custom of buying Matzahs from a bakery and that rather each individual is to bake his own Matzahs as it diminishes in the personal performance of the Mitzvah and one is unable to ensure that proper Kashrus standards are followed. However, today, the opposite is true. If every individual made their own Matzahs many would stumble on the laws due to lack of knowledge and experience, and hence it should only be done under Rabbinical supervision, who are expert in this field of Halacha.
 The reason: As a) It is a greater Mitzvah when one fulfills the Mitzvah himself rather than have another do so in his place. [Admur 460:3] b) As many of the workers today are not careful in all the detailed Halachas involved in Matzah baking, and they are thus not to be trusted, unless supervised. [Admur 460:4]
 For example, in a Chabura that I, the author, was part of, which contained many ignorant and inexperienced participants from the Yeshiva, one individual was sitting on a sack of flour in the flour room while sifting another sack of flour. Another was drinking a soda can in the flour room. Another opened the window in the baking room due to the heat and allowed falling snow to enter through the window and contact some of the baked Matzahs in the rack. All the above may not be done, and occurs when people who lack the proper knowledge and experience participate in the baking.