How on earth did you get FOUR dragons?
My current world genned *six* dragons-three male and three female. I caught a male and female, and managed to breed them by giving them the CHILD tag in their raws. Here are the world gen params:
[WORLD_GEN]
[TITLE:MEDIUM]
[SEED:3817762622]
[HISTORY_SEED:103190434]
[NAME_SEED:3942062620]
[DIM:129:129]
[END_YEAR:1050]
[BEAST_END_YEAR:200:80]
[REVEAL_ALL_HISTORY:1]
[CULL_HISTORICAL_FIGURES:0]
[ELEVATION:1:400:401:401]
[RAINFALL:0:100:200:200]
[TEMPERATURE:25:75:200:200]
[DRAINAGE:0:100:200:200]
[VOLCANISM:0:100:200:200]
[SAVAGERY:0:100:200:200]
[ELEVATION_FREQUENCY:1:1:1:1:1:1]
[RAIN_FREQUENCY:1:1:1:1:1:1]
[DRAINAGE_FREQUENCY:1:1:1:1:1:1]
[TEMPERATURE_FREQUENCY:1:1:1:1:1:1]
[SAVAGERY_FREQUENCY:1:1:1:1:1:1]
[VOLCANISM_FREQUENCY:1:1:1:1:1:1]
[GOOD_SQ_COUNTS:25:251:503]
[EVIL_SQ_COUNTS:25:251:503]
[PEAK_NUMBER_MIN:12]
[OCEAN_EDGE_MIN:1]
[VOLCANO_MIN:3]
[REGION_COUNTS:SWAMP:260:1:1]
[REGION_COUNTS:DESERT:260:1:1]
[REGION_COUNTS:FOREST:1040:3:3]
[REGION_COUNTS:MOUNTAINS:2080:2:2]
[REGION_COUNTS:OCEAN:2080:1:1]
[REGION_COUNTS:GLACIER:0:0:0]
[REGION_COUNTS:TUNDRA:0:0:0]
[REGION_COUNTS:GRASSLAND:2080:3:3]
[REGION_COUNTS:HILLS:2080:3:3]
[EROSION_CYCLE_COUNT:250]
[RIVER_MINS:100:100]
[PERIODICALLY_ERODE_EXTREMES:1]
[OROGRAPHIC_PRECIPITATION:1]
[SUBREGION_MAX:2750]
[CAVE_MIN_SIZE:5]
[CAVE_MAX_SIZE:25]
[MOUNTAIN_CAVE_MIN:25]
[NON_MOUNTAIN_CAVE_MIN:50]
[ALL_CAVES_VISIBLE:0]
[SHOW_EMBARK_RIVER:2]
[SHOW_EMBARK_POOL:2]
[SHOW_EMBARK_M_POOL:2]
[SHOW_EMBARK_M_PIPE:2]
[SHOW_EMBARK_CHASM:2]
[SHOW_EMBARK_PIT:2]
[SHOW_EMBARK_OTHER:2]
[SHOW_EMBARK_TUNNEL:2]
[TOTAL_CIV_NUMBER:20]
[TOTAL_CIV_POPULATION:20000]
[PLAYABLE_CIVILIZATION_REQUIRED:1]
[ELEVATION_RANGES:2080:4160:2080]
[RAIN_RANGES:2080:4160:2080]
[DRAINAGE_RANGES:2080:4160:2080]
[SAVAGERY_RANGES:2080:4160:2080]
[VOLCANISM_RANGES:2080:4160:2080]
On a side note, if you can get both to survive world gen there should also be a male/female pair of hydras. For me, only the female survived. I had the orc mod when I genned this world, and I didn't add in any other creatures. Some stuff was given the trainable tag, but that's about it. I ended world gen in 154 with all six dragons alive, btw. The fort's 20 years old now, so it's had plenty of ops for a megabeast to come. If you let the collossi and titans die off in gen (make them their regular size), you should have a MUCH higher chance of getting many dragons. My fort has seen at least five, maybe six mega beast arrivals.
-Albedo: They work just fine when attached to the chains. Don't know about fortifications, but they do work fine with chains. On a side note, they're also more effective against gobbos than orcs-mainly because gobbos have more clothing to ignite. Four dragons, by the way, can solo an orc siege if they don't have to face more than 2 squads at once-at least, they can at size 60 (which is what I make megabeasts so they might actually SURVIVE world gen). Unfortunately, I don't have the ability to further test this without reverting to an earlier point in my fort.
However, if on chains it seems that sometimes they don't breathe fire until they get attacked-I generally break the chains asap, but that seems to be what happens. So for me, yes, it seems they DO need a path to the target-beyond what the chain lets them. They certaintly don't attempt to fight until the enemy attacks. However, it seems that if ONE gets attacked, even if their chains aren't loose yet they all will start breathing fire if possible. I'm going to continue my mega project in that fort, but I'll do some experimenting if I can get another situation like that (in other words, regen the world/use the history seed).
I can conclude they DO need a definite path before they'll do anything, though, so be ready to support the dragons if you use a dragon defense. And don;t let them near archers if you can help it-those will kill them. They can and WILL murder even orcs in melee (in fact, my dragons kill most of their stuff with their claws, not their breath-that's actually only a small percentage) (at size 60, anyway), so keep them there. While my setup lets them use firebreath at a greater range, it might be more effective to position them around a bend in a corridor and THEN let them loose. They are, and I cannot repeat this enough, infitiely more effective if you let them get into melee-and this is supportable if you mod them to be breedable. Three may be enough, but what kills a dragon is when they get tired and slow down. Before that, they pretty much one hit everything.
To keep them alive, you have to make sure that they don't get exhausted-one dragon simply
cannot solo a siege. I only lost two dragons, and the first was when I let it solo an orc siege; it got swamped and couldn't handle all the orcs, even when I belatedly rush my Urist McNorris champions to help out. The other was a hatchling that wandered around. If you can have them support each other, dying is not an issue so much. They may get some injuries, but generally nothing major unless you get unlucky. Incidentally, unlucky accidents are why I let them breed-the veteran dragons can retire to furnished rooms for their services, while the fresh replacements get named. By the way, dragon names are not random-they relate to fire and treasure without exception. That is, if they gain their names through combat. One adopted will have any old random name.
Dragon hatchlings are not a viable defense-they will not breathe fire nor will they attack-and if attacked, then they run like any normal baby animal would.
I let my three champions handle archer squads, and let the dragons take care of melee. For me, however, this murders my framerate horribly (since I turn temp on). A 5 minute battle in the game works as a 1-minute movie-might be due to having over 20 caged skeletal stuff and uncountable gobbo clutter. As a side note, this originally wasn;t designed as a DEFENSE, but as way to use my dragons to ignite the world so all the gobbo clothes would burn off. Which, by the way, didn;t work-the map might have been too arid, but it just seems that the fact that dragon fire reduces stuff to ashes makes it harder for it to ignite grass. By the way, give them the fire imp's heat dam blocks for everything. It keeps them alive. I give this seed so you can give the dragon defense a try, since to be honest this is the first time I have seen a world with so MANY dragons. Just keep your champions from doing anything stupid around the dragons, and there shouldn't be a problem
P.S. If this post seems somewhat disorganized, it's probably because I went back and modified some parts after i finished writing it.