Here's a question we've had pop up several times. At what point can you use cards such as Animal Husbandry to heal units? Can it be used immediately after taking the damage or must the unit survive first then be healed of the damage? For example I play an Infantry unit with a value of 2 then my opponent play an archery unit on my Infantry front also with a value of 2. Could I use Animal Husbandry to immediately heal the two damage and then kill the archer and if that is the case what rule exists for the scenario where I played a infantry with a value of two and my opponent plays an archer with a value of 3. This would leave a front with both troops left alive and leave the other player unable to play again on that front. Or do we simply apply Occam's Razor and assume that unless a unit survives it cannot be healed.

From P25 of the rulebook:

"Some tech cards have resource abilities that are used during
battle. These abilities are always used before or after attacking
an enemy front, never during – even if some of their effects may
last through an attack."

In other words, yes, the unit would have to survive the attack to benefit from that ability. In the early game that'll be somewhat useful, but not extremely. In the late game, however, it becomes much more important. (in my experience)