Ball pythons Husbandry:
Ambient daytime temp: 80-85F (26.7-29.4 C)
Hot spot (basking spot) 90-95F (32.2-35 C)
Night time ambient can drop to 75-80F (23.9-26.7 C)
Humidity: 60-70% (or provide moist hide especially around shedding time)
Min. Sized enclosure for Juvenile ball housed alone
20" long by 10" wide (50.8 by 25.4 cm) minimum. Full sized adults should have cage 36" by 12" (91.4 cm long by 30.5 cm wide). This is floor space. Height isn't really important, as long as its high enough the snake can move over hides and water dishes without being wedged against the lid.
Rat Snake Husbandry (assuming its a Texas Rat snake)
Ambient temperatures of 74 - 82F
Hot spot about 85-90F
Min. sized enclosure should be at least 2/3rds the length of the ratsnake in length and a third in width.
I know you are getting rid of the rat snake but pointed out the husbandry requirements to show a 4' cage is not adequate housing for the number of snakes you have in there.
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Male ball pythons will wrestle and fight each other as soon as they reach breeding size/age. Male ball pythons tend not to eat either when fighting each other and chasing females to mate. Being constantly in the same cage with each other..your males are likely to starve to death trying to fight each other and mate.
You have a full grown male ball python with a baby male (the pastel). Even though you feed separately, prey scent lingering on the smaller ball could trigger a strike by the larger and you may find you have one very big ball python and no more pastel ball. Same thing when you add the female spider.
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Lets say all your ball pythons babies make it to maturity. Your female is going to end up being bred too young or not at a good weight, as the males will jump her as soon as she starts smelling like a mature female. Under weight and under aged females can produce fertile eggs, but have a much higher chance of dying, especially if you don't take out the eggs.
Ball pythons can incubate their own eggs, if the conditions in the cage are correct. But the female won't eat at all during incubation (around 60 days). So if the female is too young and not a good weight, gestation and incubation may deplete her so badly she won't survive to breed another year.
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If your goal is to successfully breed your snakes, and have healthy young and adults after breeding is over, follow the advice posted by the majority of people here and the various sources provided already.
We can point out the information that has worked successfully for all the top line breeders and the small hobbyist breeder over the years but if that isn't the information you want to hear, then there is no point for you to ask for advice.
Your big cage may seem perfect for all your snakes (current 3 with a 4th on its way, though it'll replace the rat snake, so back to three), even if you have plenty of hides in hot and cold sections of the cage so all can have their idea basking/cooling spot, you are risking your snakes in such a setup.
Also, since you feel racks are too small and cruel... once you have two full grown ball pythons that cage is too small to house them both. It is great for a single large adult ball python but once you have a second full grown male, you are going to have to remove at least one male. The cage isnt' really big enough for a large male and large female either (and do keep in mind female ball pythons tend to get larger...as big as 5' in some cases, and well over 4000g (8.8 pounds).
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You asked if the males fighting will be a problem?
Yes it will be a problem. It will risk the health of your snakes as both will be highly stressed, won't eat and eventually one or both will die.
Assuming of course your current adult male doesn't eat the smaller male and the female spider you have on its way before either can reach adult growth. But you can just buy more snakes right?
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PHLdyPayne