just reading thru this thread, thought i'd put my 2c in... maybe my experiences will help others who might have problems or questions...
i just got done hatching some eggs for a friend. 12 shipped RIR eggs (1 was cracked and waxed), 6 of her own 'homegrown' (3 from silkie 3 from sfh pullets) and 3 of my own (2 EE 1 buff orp/)... these eggs were shipped directly to my friend, who lives about 2 hours away now (wish she hadn't had to move). our own homegrown eggs were not purebred, but mixed flocks.
for background, this is my setup...
I use a hovabator picture window with wafter thermostat (have 4 actually) with added fan (use 12v computer fans running on 6-9v cell phone chargers) and egg turners for 3 of them. the 4th is a dedicated hatcher only, with a disposable plastic container (about 2cup size rectangular) with a hardware cloth wire lid (to keep chicks from jumping in) for humidity. The hatcher is lined with paper towel and a 30-egg crage (either paper or plastic) on top of the paper, with the bowl in one corner for the hatching eggs. I prefer this to laying them on the floor, as hatched chicks seem to roll eggs around horribly. when the bowl is filled, the humidity goes to about 60% and will vary once chicks start hatching, up to about 75% briefly. temps on hatcher and incubators are all right at 99.5 but vary slightly (+/- 1 degree) depending on what the heating element is doing (just turned on, just turned off).
i dry incubate, usually between 10 and 15% this time of year, 15-20% in the summer. (yes, you read that right). I ignore everything, for the most part, candling on day 5, 7 and 10 to check for growth (some darker eggs are harder to see early on) and again when eggs go into the hatcher on day 18, candled once more on day 19 to check for internal pips, unless i see external pips then i leave it be.
so these eggs were shipped to my friend, then driven the next day up to me and incubated immediately, with the turner set as flat as i can catch it (no tilt). I start turning all eggs on day 3, regardless of shipped or local. by day 10 it was obvious 3 of the shipped, the 3 sfh pullet & 1 of my EE eggs were clear. the cracked egg was growing well even!
on day 18, all the eggs were still cooking along, on day 19, it was obvious most had internally pipped. by the end of day 20 i had 8 chicks hatched and were removed to the brooder (i use a squirt bottle to wet the paper towel on the bottom when taking chicks out, to get the humidity up fast), 4 more pipped who were all out by the next morning. the cracked egg appears to have quit around day 19 or so, and the other pipped in the small end and appears to have suffocated in it's own blood when a few vessels were ruptured while zipping. not sure what day that happenned, as i discovered the fact when i removed the last 4 to the brooder.
calculating hatch rate, some people count infertile/clear eggs, others don't. i don't tend to count clears myself, since that had nothing to do with my own hatching abilities, so that would give me 78% hatch on the shipped eggs, 100% of our homegrown eggs (even tho hers were transported by car 2 hours,so technically shipped as well).
with the dry incubation, i've had great results on shipped eggs from a number of sources (bhep, DMRippy, luckypickens to name a few). from those same people, using higher humidities (prior to going totally dry) hatch rates were around 20%, with most lost during hatching because they were too wet.
oh and i live in sw virginia, where humidity in the house is 35-40% over the winter and 60%+ in the summer...
hope this helps others...