personally I don't have the pets show up in 25mans, there's just not enough room to show up to 15 pets along those 25 raiders (don't come talking about 40man raids please - IIRC healers was assigned to different groups to heal, not the entire raid). They do get healed from JoL (I believe, not sure) and can be targets for smarttarget heals (CH, WG, CoH ect) and that is probably about what you can expect them to get healed with in a 25man. That is generally enough though, as pets take 90% less AoE damage.
In a 10man and lower however, I have them enabled, and I do throw a heal on them every now and then, but more often than not I'll just let it bounce off a melee instead.
You can't reliably expect healers to always heal your pet. No matter the situation, it's better to save an actual raider than a pet and as such you should use your own pet-healing abilities if needed.