Normally, hatching eggs are transferred from setter to hatcher at approximately 18 days. This is slightly dependent on the day of hatching, as most hatcheries do not want to transfer eggs or pull chicks on saturday or sunday.

Eggs for hatch on friday are therefore normally transferred on tuesday,
Eggs for hatch on thursday are normally transferred monday,
Eggs for hatch on monday are normally transferred on thursday,
Eggs for hatch on tuesday are normally transferred on friday.
As a consequence, wednesday is normally a non-hatching and non-transfer day.

Also, chicks that hatch on friday or thursday are relatively stays for a longer period of time in the setter and shorter in the hatcher than chicks that hatch on monday or tuesday.

As eggs do not have to be turned anymore after approximately 14 days of incubation, we can transfer earlier than 18 days. This can be sometimes beneficial for instance, if temperature control in the hatcher is better than in the setters. Of course, if this would be a structural approach, more hatchers has to be placed.

Although it is not a common practice especially in a broiler hatchery, transferring as early as 14 days has no negative effects on hatchability, provided that the hatchers can create the same conditions for the embryo as the setters are able to.

However, if data analysis shows that an early transfer has a positive effect on hatchability and/or chick quality, it can indicate that attention must be paid to the control in the setters. If late transfer has a positive effect, the attention must be directed to the hatchers.

If in-ovo injection is used, for instance to administere Marek's vaccine, the timing of transfer is very crucial. The injection of the egg, that is done on the same moment, needs a distinct level of development of the embryo which means a limited time window during the incubation process. When in-ovo injection is used, possibilities to alter the moment of transfer are much more limited.