Of course, the IDF did have a valid military reason to destroy the chicken coops:
123. The command investigations conducted with regard to this incident reveal that the Sawafeary chicken coops were destroyed for reasons of military necessity.Will human rights groups say that Hamas is violating the same treaties they accuse Israel of violating?
124. Specifically, the investigations revealed that the area around the Sawafeary chicken coops was occupied by an IDF ground force beginning on 4 January 2009, as part of the ground maneuver, with the intention to take control of rockets and mortar launching sites and reducing the number of terror attacks on Israeli territory. The force took positions in several houses, including one house that was adjacent to the chicken coops. This positioning was necessary to secure the area for military operations against Hamas and to protect the IDF troops in those operations. The IDF’s defense plan for this area needed to meet three serious threats to the safety and security of the IDF troops: the firing of anti-tank and RPG missiles on IDF positions; sniper fire; and infiltration of terrorist operatives into the immediate vicinity of the forces in order to plant and detonate explosive devices, including by suicide bombers.
125. The terrain in the area made this location more dangerous for IDF forces. The area was agricultural in its original use and thus included many orchards, groves, and greenhouses, located between and around the houses occupied by the IDF. This made it harder for the IDF to identify Hamas positions and fighters. The threat was not theoretical—on 5 January 2009, an RPG missile was launched at one of the IDF positions in that area. In addition, several shooting incidents occurred originating from the orchards located to the south of the chicken coops.
126. In order to overcome these threats, the IDF decided to create a security zone around each of the IDF positions with a perimeter of 20–50 meters around each post, which would allow uninterrupted observation and firing capabilities for the force in each position, as well as joint protection among the different IDF outposts. These security zones allowed IDF forces to anticipate at an earlier stage the approach of terrorist operatives.
127. The Sawafeary chicken coops were located only a few meters away from one of the key IDF positions. The IDF position was, itself, dictated by the lay of the terrain in the area. As the command investigation determined, this IDF position could not be adequately secured if the chicken coop structures were left intact. The demolition of these structures was needed to allow a clean line of sight for protection of IDF forces. The investigation also determined that the decision to destroy the coops was consistent with the demands of the principle of proportionality: there was a compelling military need for the area to be cleared for the safety of the IDF forces and for the success of IDF operations against the Hamas forces operating in the area. The local commanders determined that these advantages outweighed the damage to private property that would result from the demolition. The commanders avoided the destruction of residential buildings or other facilities in the area, when such destruction was not required by military necessity or appeared to be disproportional.
No, and for good reason: Hamas wasn't aiming at the cows. It is aiming at Israeli civilians. So the food supply was only accidentally destroyed in pursuit of murdering people.
Hamas is safe from worrying about the UN going after it.
Incidentally, this shows a small example of what many populated sites in Israel would look like if Iron Dome wasn't protecting people. And this was a small rocket.
(h/t Yoel)