What happens when guppies give birth

It’s not uncommon for guppies to die after giving birth, and in some cases, even during birth. Unfortunately, there are many reasons that this can happen, and some of them are beyond your control. However, in some cases, you can reduce the chance of your fish dying after giving birth. (source)
Female guppies are usually in labor for between 2 and 8 hours. Labor is usually an uncomplicated affair with the guppy giving birth to between 40 and 80 babies. (source)
https://www.youtube.com/watch?v=dg1PV6zzTu4
Yes, they do. Though guppies are one of the calmest breeds and are generally pretty peaceful, they often end up eating their fry. This weird and disturbing activity is termed as filial cannibalism. (source)
Guppy Fry Tank Maintenance Keep the water temperature at 80 °F. It is not necessary, but warm water speeds up the metabolism of the fish. … Make partial water changes often. Fresh water will also benefit the growth of the fry. … Keep the lights on for at least 12-16 hours a day. (source)
Guppies don’t give birth to all their babies at once. That’s because they don’t lay eggs like other fish. So, they have to give birth to one fry at a time. That is why they need more time for breeding than other fish. (source)
One of the first questions people usually ask is, “How do guppies have babies?” When a guppy gives birth, the females will “drop” 2 to 200 baby guppies, called fry, typically in four to six hours. If she is stressed, however, the process to give birth to all the fry can take up to 12 hours. (source)
https://www.youtube.com/watch?v=YTWYuKb4Pxw
It is not normal for guppies to lay on the bottom of the tank. In my experience, there are a number of reasons guppies lay on the bottom of the tank and these include illness, stress, and poor water quality. Pregnant females may also lay on the bottom of the tank prior to giving birth. (source)