Are there any concerns with the process of making Tekhelet and the issue of tzar baalei hayim?

The issue of “tzar baalei hayim” is undoubtedly an important one which keep us sensitive to all of God’s creations. Included in that, for example, is we must feed our animals before we feed ourselves. That being said, it must be clear that this does not mean we hold the same banner as animal rights groups who are against any and every use of animals. In fact just the opposite, God commanded (Gen. 1:28) Man to rule over the animal kingdom and make use of it for the betterment of mankind. There are countless examples – from the mitzvot of offering korbanot, and the statement in the Gemara that true rejoicing is with meat and wine; and of course the three dyes of the Mikdash (tekhelet, argaman, tolaat shani) are all from the animal kingdom. The only proviso to the overreaching divine command of “Subdue [the earth] and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that creepeth upon the earth” is that we not abuse the animal kingdom. “Tzar baalei hayim” is a warning (a) not to harm animals for no reason, (b) not to inflict undue pain when we are utilizing them for legitimate reasons. However, the notion of “undue pain” must not be taken out of context. That is to say, when we need to slaughter a cow, we are not bidden to anesthetize it, but simply to perform the act in a way which will not cause more suffering than is normally attendant with such a procedure. At the end of the day, slaughter is slaughter and there is going to be some pain involved. (Indeed, it should be noted that though we try to minimize suffering to the animal that is being killed, the actual killing of an animal is not considered “tzar baalei hayim” – (see Shu”t Har Tzvi, Orech Hayim I:194). So in answer to your question regarding the dye extraction from the hillazon (Murex trunculus), we perform the procedure in its normal way without causing undue pain over and above what is naturally attendant in killing a living creature. The snails are kept in water for as long as possible before removing the glands. After the gland is removed the snails have been used for bait or given to non-Jewish people to eat in the area. – Mois Navon.