Boa Constrictor Care

Heating

I generally recommend keeping boa constrictors with a hot side of 88-90F, ambients of 80-85F, and a cool end of 70-75F, if allowed by the size of enclosure. Smaller enclosures are harder to offer a larger temperature gradient in, so I generally recommend not providing a cool end under 78-80F so that there's not such a sharp drop in temperature between hot and cold sides.

The tool used for measuring temperature and humidity is important. Analog and stick-on thermometers are generally not considered accurate, and I would avoid depending on these as your sole temperature readers. Digital hygrometers (not to be confused with hydrometers, which measure water density) are also generally more accurate than analog. If your hygrometer can also be calibrated, even better. Otherwise, you may need to perform a salt test and record the discrepancy so you know how to change the readings for accuracy. Hygrometers measuring overall humidity of the enclosure should also be a few inches above the bedding, but placed on the cool side only.

A thermal gradient can be achieved by planning out the layout with plenty of ground space, height, or a combination of the two. For example, in my 2' tall enclosures I divide the enclosure mentally into 4 quadrants. Top corner where the heat source is, is the basking area. The top corner opposite the heat source and bottom corner under the heat source are the ambient areas, and the far bottom corner is the cool end. Usually there are 3 temperature sections, with the upper corner and bottom corner under the heat source being equal, but that changes in winter when the room temps drop. If there isn't room for all of that, I do not advise allowing any part to drop below 80F.

These temperatures can be achieved by using an ambient heater, such as an RHP, CHE, halogen, or Tungsten bulb. I do not recommend any non-white colored bulbs at all, and any lights should be on a timer to shut off at night for a proper day/night cycle. All bulbs should either be outside the enclosure, or inside and covered with a bulb cage to protect your snake from getting burned. If you are struggling to meet these temperatures inside the enclosure, heating the entire room to 70-80F helps tremendously. In situations where this isn't possible, insulating the enclosure to hold heat may be required. Also keep in mind the material you use for your enclosures. Glass holds heat the least effectively, PVC is a step up, and plywood and melamine hold heat the best but may be more difficult to provide. PVC and tanks are widely available, wooden cages are usually custom built.

You can also use belly heat only, such as heat mats or heat tape, so long as the enclosure is kept in a room kept at a minimum of 75F. Heat tape and pads are not recommended for wooden enclosures, as the heat doesn't penetrate the wood effectively, and having either inside the enclosure is not safe for your animals. I do not recommend heat cable or heat rocks whatsoever, even with a thermostat.

All heat sources must be controlled with a thermostat; dimmers and rheostats are not adequate as they require the constant attention of the keeper to maintain temperatures. All bulbs should be on a dimming capable thermostat as pulse and ON/OFF reduces the life expectancy of the bulb and a light turning off and on can disturb your animal(s); RHPs, heat tape, and heat pads can be set with ON/OFF, pulse proportional, or dimming thermostats.

When setting up a heat pad, or heat tape, the thermostat probe must be outside the enclosure in between the pad/tape and the bottom of the enclosure. To set the thermostat properly, either measure the empty enclosure, or push any bedding aside that's over the where the heat pad/tape is and measure the surface temperature of the floor with a temp gun. Set the thermostat so that at max power, it reads desired hot spot temperature. I set my heat tape higher than my ambient heaters, at 95-96F, as they seem to digest a bit better and thermoregulate more vs only hugging the heat.

When setting up an ambient heater (RHP, basking bulb, CHE, etc.), set the thermostat probe 1"-3" above the bedding directly below the heat source. Allow 24-48 hours for the enclosure temperatures to stabilize after making any changes, as it takes time for the air temperature inside an enclosure to heat up or cool down.

Humidity

Boas are a tropical species, and benefit from higher humidity. I generally recommend at least 70-80% humidity, whether in shed or not. This can be achieved in a variety of ways, and depends heavily on the area you live in and the particular set up you're using. Some general tips to help if you notice issues achieving a higher humidity:

If using a screen top enclosure, be sure to block off as much of the screen as you can to reduce how much moisture escapes out of the top, while still allowing some fresh air in.
Use a high humidity bedding, such coconut coir, coconut chips, or sphagnum moss. These can also be used in any combination. Dump ater directly into the bedding, and mix evenly. Bedding should be damp, not wet. Allow to completely dry before repeating.
Offer a large water dish big enough for the snake to soak in.
Use a humidifier in the room to raise the humidity of the whole room, but don't go overboard here so you don't damage your home. It doesn't need to be the levels your boa constrictor needs, just raised enough the enclosures maintain humidity better.
Offer a humid hide with wet substrate that is changed regularly to avoid mold.

Feeding

I recommend frozen/thawed (f/t) feeders for the safety of your snakes, humane handling of the feeders, ease on your wallet, and convenience of not having to hunt down a source every feeding day. Thaw in cold water until the feeder is soft all the way through. You can then either allow the feeder(s) to sit until the water and feeder reaches room temperature, or replace with hot tap water and allow to warm for 5-10 mins until it retains a warm feel once dried. Cold running water will thaw feeders faster, but will require a period in hot tap water to warm. Towel dry excess moisture, and offer feeders from tongs, holding by haunches or legs with head facing snake for a more stable presentation (holding by the tail can make them swing unpredictably and reduce strike accuracy from the snake).

I take a more conservative approach with my animals, preferring slow growth if it means my animals are healthy. I expect a breeding size female at 5-6 years old. With that in mind, these are strictly just recommendations with that goal in mind. I will adjust feeding based on the individual's needs throughout the year. This guideline is mainly for pet animals and not breeders, though my breeders' schedules don't change much except during courtship and up to 2 years after a female drops a litter. This is more than adequate for raising up breeders, females with more than 2 years between pairings, or males not actively breeding.

I keep prey size small, especially for adults. For babies, I aim for meals roughly equal to girth or slightly larger so that it leaves a barely noticeable bulge. There shouldn't be any scale separation and the bulge should be gone in 24-48 hours. Adults, I want meals smaller than girth so that there's no noticeable bulge at all.

Frequency depends on the size of prey, feed prey size based off of girth/size of snake, and not age as not all snakes grow at the same rate or reach the same adult size:

All mice (or equivalent sized prey) go 10-14 days
Weaned rats (~20-40 grams) and equivalent sized prey go 14+ days
Small rats (~40-80 grams) and equivalent sized prey go 2-3 weeks
Medium rats (~80-150 grams) and equivalent sized prey go 3-4 weeks
Large rats (~150-300 grams) and equivalent sized prey go 4-6 weeks
XL/jumbo (300+ grams) and equivalent sized prey go 6-8 weeks

I avoid XL/jumbo if I can, only offering it to larger adults for 1/3 or less of their yearly diet if I can't get rabbits, as the fat content is best avoided. I don't offer Guinea pigs, pigs, or colossal rats at all, and avoid jumbo mice/rats due to fat content.

While the 10-15% rule gains popularity every year, and numbers are easy to follow, I highly recommend against utilizing this rule as it is a very heavy feeding schedule. My averages stay closer to 6-8% of body weight with a max of 10-11% (which leaves a large bulge with scale separation) for babies and 2-6% with a max of 8% for my biggest adults. The bigger the boa, the bigger a meal is proportionally to girth when offering by weight. So 10% on a baby is a smaller meal proportionally than 10% on an adult. If you use the 10-15% rule, I wouldn't use it on boas over 1, maybe 2 years old.

A varied diet is best, if you can provide it. I offer mice, ASF, hamsters, and day old chickens/quail to young boas. Rats, rabbits, chickens, and quail to larger boas. Gerbils are also another good feeder, though I haven't offered any to my snakes yet. *Avoid any wild animals due to danger of parasites and poisons.

Optionally, I reduce or stop feeding in the winter for boas with an adequate body tone. For babies after their first year, I feed half as often for 4 months. The following year, I will completely withhold food for 90 days every winter. I will up food intake a few feedings before and after a fast, and feed normal sized meals if feeding half as often. I do not drop temps while fasting or reducing feeding.