After the introduction you will hopefully observe some copulation. Copulation can sometimes occur only at night. After the 3 weeks the retics should be separated. In comparison to other pythons the copulation procedure is relatively short with breeding lasting under half an hour each time and only occurring 3-5 times.
After the female ovulates (witnessed by a short-term swelling just past mid-body that goes away after 24-48hrs) she will begin to develop the eggs inside her. It is worth noting that once the female has ovulated she will lay something at the end of the gestation period, even if that is a clutch entirely of “slugs”.
After 45-60 days (approx.) she will have a pre-lay shed. You then have a further month or so to wait to see what she will lay. Females will generally lay between 25-80 eggs but numbers above this have been recorded. This number is affected by the number of times she has been bred before, how old she is and how big she is. An animal that has bred before will generally have a higher amount of eggs than one that has never bred before. The older and bigger they are before being bred can increase the initial clutch size which will make later clutches larger than smaller animals that have been bred several times. In this way it is beneficial to everyone if you take your time with breeding and only do it when the female is in perfect health.Females may typically lay with their bellies up as the eggs grow larger and they become more uncomfortable.
Like most pythons, female retics incubate the eggs themselves in the wild all the way to hatching, they "shimmer" in order to change the temps the eggs are incubated at. This is done by twitching muscles. As a result, be very careful when removing the eggs as the female is likely to be a little upset about you taking them away from her. If possible, it is best to remove her from the cage prior to taking the eggs. If not try placing a board in the cage separating the two sides, so that she is on one side and the eggs are on the other. This will minimize your chances of getting nipped. Although how common it is I am unsure of there are several cases where the female has entered a catatonic like sleep while laying her eggs. This results in a highly docile snake that will let you remove the eggs as and when she lays each one. The female should resume eating in about 2 weeks although it is common for this figure to be highly varied. It is more important to get her feeding again if you plan to breed her the next year as she will need to be brought back up to a good weight for her own safety although I dont personally recommend this. There are current studies been undertaken to try to judge just how often female reticulated pythons breed in the wild and if this varies with the age of the animal. Until this report is published I would suggest that breeding every other year is a good figure to aim for.