there seem to have been a lot of post about hatch rates and the effects of buying via post. SO I had a quick look at what the scientists are saying and there are some really intersting things being studied
the first study looked at the Effects of pre-incubation upside-down positioning of eggs. "The results indicated that keeping eggs in an upside-down position reduced (P < 0.05) hatchability by 4.3% compared with the Control (normal position) group. Also, reversed egg positioning significantly increased relative intestine weight (P < 0.05) and percentage of embryo mortality between 18-19 days of incubation (P < 0.01)."
What would be intersting would be to see what effect it would have to have upside down positioning for say 4 days followed by 1 day right way up....i will go look at see if this has been done yet
the next study I looked at looked at the effects of cold stress on egg fertility this looked at 4 temperature groups (treatments): 1.2 degrees C, 1-2 degrees C, 2.5-3.9 degrees C, 4-6 degrees C, and a control group, 21-22 degrees C. Cold stress had a significant effect on chick length, hatchability, Cold stress also had a significant impact on the number of cull chicks; percent of string navel, button navel, total string, and button; omphalitis; full body cavity; red hocks; dehydration; dirty chickens; and stubby down. Cold stress affects performance during incubation and overall chick quality.
If eggs are sent by post it is reasonable to assume that they will experience times when they are upside down d time when they may be exposed to the cold (particularly in the winter if held overnighht in sorting locations) so maybe we should not be so surprised that we get low hatching rates form postal eggs. It seems to me that we either accept this, work with delivery companies to reduce this ie adherence to signs saying this way up, an minimum time in cold environments, or we pick up the eggs ourselves.