Bava Kamma, Chapter 2, Mishnah 1. In this section we will turn our attention to an expanded explanation of the category of "regel" - damage caused while an animal behaves naturally and walks in its usual manner.
"Keitzad haregel muedes leshabeir bederech hiluchah" - How is the foot considered forewarned to break items as it walks:
We have already said that regel damage - an animal causing damage during its normal walking - is considered muad, meaning expected damage, and therefore the payment is full damages from the outset. The Mishnah asks: How is it expected from the outset that damage will be caused, to the point that a person is required to be concerned about it? And the answer is: "leshabeir bederech hiluchah" - to break items as it walks - the animal walks around and tramples with its feet, its tail swats at flies and knocks things over, and all of this happens as it walks.
"Habeheimah muedes lehaleich kedarkah uleshabeir" - The animal is forewarned to walk in its usual manner and break items - furthermore: the animal is expected to walk normally and break things not only with its feet or its tail, but even with objects attached to it - a plow, a saddle, and the like. The saddle protrudes from the sides of the animal, and if it knocks items over while walking, this is also included in what is expected, since it is not the animal's body itself but an extension of its body, and a person must take this into account.
All this applies when it walks with its feet in its normal manner. But the Mishnah continues: "Haysah meva'etes, o shehayu tzeroros menatazin mitachas ragleha veshavrah es hakeilim, meshaleim chatzi nezek" - If it was kicking, or if pebbles were flying from under its feet and it broke utensils, he pays half damages - whether the animal kicked a utensil and knocked it over, or if small stones flew from under its feet as it walked and broke a utensil, the payment is only half damages.
The Mishnah states many things here, and in fact, two completely separate matters are compressed together within it. The common denominator between them: both are not standard regel, both are done using the foot, and for both the payment is half damages - and for this reason they were taught together. But regarding the actual law, there is no connection between them at all.
Let us separate the two matters:
Kicking utensils: This is classic keren. The animal acts with an intent to damage, deliberately trying to break and smash. We have already said that under normal circumstances the animal is considered tam, meaning it is not expected to kick and cause damage, and therefore the payment is half damages - because it caused damage intentionally, which was unexpected.
Flying pebbles: This is not keren at all, but rather is included in the category of regel. However, we have a Halachah leMoshe miSinai, a tradition going back to Mount Sinai, which is the special law of half damages for tzeroros: when the animal causes damage neither with its body nor with something attached to its body, but with something propelled by the force of its body that is not attached to it - such as a stone that flies from under its foot - the animal's owner is obligated to pay only half damages. This is not because the matter is related to tam, nor is it because it is an intentional damage of keren; everything here is regel, but this is a special rule: when the regel damage is done by the animal's force - known for short as tzeroros - only half compensation is required.
The practical difference in the public domain:
When a person's animal causes damage by kicking, he is obligated to pay even if the incident occurred in the public domain. If Reuven's cow and Shimon's cow are walking side by side in the street, and suddenly one kicks the other and causes damage - its owner is obligated to pay half damages, since this is a subcategory of keren, a subcategory of intentional damage, and it applies even in the public domain.
In contrast, there is no liability for regel damage in the public domain, since animals are permitted to be there, and if the animal caused damage through regel - doing what animals do and going on its way - its owner is exempt. Therefore, if the cow kicked up a stone in the public domain and shattered a utensil, there is no liability at all here, not even half damages, because tzeroros are a subcategory of regel, and the laws of regel do not apply in the public domain. The law is stated specifically in a case where the damage occurred in the injured party's domain, such as in his courtyard: there the animal has no business being, and therefore if it trampled his flowers as it walked - this is regel and he pays full damages, and if it kicked up a stone that damaged them - he pays half damages.
Explanation of the law of tzeroros in the Mishnah:
"Darsah al hakli veshavarto venafal al kli veshavoro, al harishon meshalem nezek shalem veal ha'acharon meshalem chatzi nezek" - The animal trampled on a pot with its foot and smashed it, and one of the shards of the pot flew and knocked over a vase, which also broke.
"Al harishon" - full damages: The pot that was trampled under its foot is a simple and familiar case of regel, and therefore he pays the full damages.
"Al ha'acharon" - half damages: The vase that was knocked over by the shard of the pot was damaged only indirectly. The damage came from the force of the animal, but not from its body at all, and therefore this is the law of tzrorot, and the owner pays only half its value.
It is worth noting that the literal translation of the word "tzrorot" is pebbles, even though in the case before us this law has no connection to actual stones.
The Law of Birds:
"Muad lehalekh kedarkan uleshaber" - The roosters are expected to walk around and do what roosters do, and in the process break objects by their jumping and by the flapping of their wings as they pass from place to place.
"Hayah dalil kashur beraglav" - There is a version that reads "deli", meaning a bucket that is tied to its foot. But the word "dalil" means anything that dangles and swings (hence "dildulin" - dangling parts): a rope, a string, and even a bucket for that matter - anything tied to the rooster's talon. If the rooster sent the rope or the bucket flying with its kick and this smashed an object, this falls under the category of tzrorot and he is liable for half damages.
"O shehayah mehades umeshaber et hakelim, meshalem chatzi nezek" - There are several explanations for the word "mehades": some say it means he jumps and dances around, and some say it means he scratches at the ground and kicks up stones. Either way, when he kicks up something that knocks over and damages, we again have the law of tzrorot before us, and therefore he pays half damages, since the damage was not done by its actual body.
Clarifications that are not explicit in the Mishnah:
Something attached to the body - full damages: If a knife had been attached to the rooster's back leg (as is done in cockfighting, Heaven forbid, where small blades are attached to the birds' legs and they are allowed to tear each other apart - a terrible practice), and as it walked the knife struck a vase and knocked it over - this is full damages, exactly like the law of the saddle, since the object is attached to the animal.
Something propelled by its force - half damages: When the animal kicks and sends something flying from it - stones, a bucket, or that object that was tied to its foot - the object is now propelled by the force of the rooster, but this is indirect damage, and therefore half damages due to the law of tzrorot.
The wind of the wings: The same applies if the rooster flapped its wings and the wind generated beneath them knocked over the vase. Here too, the damage was not done by the physical body of the animal but by its force, since the wind was generated by the force of the flapping of its wings, and therefore this falls under the category of tzrorot and payment of half damages.
The place of liability: This liability exists specifically in the domain of the injured party and not in the public domain - meaning only when the rooster was in a place where it had no permission to be, such as in the courtyard of the injured party, and damaged his objects there.
In summary: In this mishnah, the category of regel was explained - damage expected from the normal walking of the animal, including damage caused by objects attached to its body, for which one pays full damages. We also saw that the mishnah included together two separate laws that pay half damages: kicking, which is a toladah (subcategory) of keren and is liable even in the public domain, and tzrorot, which are a toladah of regel by virtue of a Halachah LeMoshe MiSinai and are completely exempt in the public domain. The basis of the distinction is between damage done by the body of the animal or by what is attached to it - for which there is full damages, and damage done solely by its force - for which there is half damages.