There can be two possibilities in the above case. 1. If the fertilisation has taken place and only after that fission has taken place, then it is difficult to predict the number of eggs involved. This is so because even one egg can also undergo fission to produce six fertile zygotes, which in turn can give rise to six puppies. 2. The other situation may be relatively unlikely, but there can be a possibility of multiple eggs undergoing fertilisation at the same time. In this case, either there are six different eggs produced, or most of the time one egg undergoes fission before fertilisation takes place, and each fertile fragment can then accept a sperm and produce fertile zygotes.