Why is my 4-month rescue puppy scared inside but playful outside?

This is going to take time and a lot of TLC and some one on one time. Give her lots of treat and get her to play more. Unfortunately, it just may not be in her personality to be as playful and free as the other dog. Every dog differs and some need different type of attention than others. It is just important to pay attention to these cues and treat each dog as such. Just give her more times and she will likely continue to come out of her shell but just know it may not be to the same degree as your other dog. I hope this helps!

Poor little thing. It can take some time for dogs that are scared and poorly socialized to adjust. I find that it can be a big help and confidence booster for them to see you interact with another dog. Sometimes they can also relate better to having another dog around. That being said, this should be a calm, easy going and non threatening dog to her. Perhaps an adult sweet friendly dog that is a similar size. It is important for her to eat and drink, so you may have to put those things in her kennel where she feels safe for now. Continue to be patient, talk in a calm and gentle voice and she will eventually learn to trust you. She lacks confidence right now and that does not come overnight, I would consider having her interact with you and another dog if it is the right dog.

Behavior training would be a great way to help her gain confidence. You can look into puppy socialization and obedience classes in your area. I'd also recommend asking any strangers to allow her to approach them, and to offer a treat. Sophia Yin's website is a great resource for behavior questions - this link has good information on socialization in general: https://drsophiayin.com/blog/entry/puppy-socialization-stop-fear-before-it-starts/

In situations such as these, time is your friend, as well as patience. 4 years living solely outside is a long time for a dog, and that's a lot of years of work to reverse. You may want to treat Perseus as if he were a puppy, starting with a similar routine for feeding, potty training, etc to get him used to being around people and in/out of a house. Getting him used to you can take time. Always approach by talking calmly and gently and tossing a treat toward him. Not directly facing him and/or crouching down can also make you less intimidating and scary. Let him approach you first rather than you approach him, and be sure to quietly praise or offer treats any time he does. As he gets more used to you, you can then treat only when he allows petting or approaches you and accepts gentle handling. This can take a lot of time, so patience and always maintain a calm presence can help. It is also a good idea to speak with a trainer or behaviorist in your area who can come to the home and offer more tailored advice for how to help Perseus. They can help formulate a training plan as in the case of a behaviorist may also be able to recommend medications to help keep him stress free and relaxed as he learns how to be a dog.

Poor Lillian. Make every effort to get her outside to potty. Also work on making her more comfortable. It's a big change for her. Once she is comfortable in the house, you can begin trying to get her comfortable outside. It's possible something has scared her in the past and now she has developed a negative association. You may try to counteract this by creating a positive association. Begin by having a high value treat or toy. Start playing/a training session inside the house by the door way. Do this for a few days. Once Lillian seems comfortable playing by the door way, toss the toy or treat outside and allow her to retrieve it and come back inside. Do this until Lillian is comfortable. Then move outside by the doorway way. Gradually move further and further away from the door way. Then begin gradually decreasing the play time and just hanging outside with her. Try not to leave her outside unattended until she seems comfortable. I hope this helps.

Give him some time to acclimate. A pheromone product, such as the Adaptil collar or DAP plug in diffuser, may decrease any anxiety. Consider short visits to a dog park or short walks to get him further acclimated. Praise and reward him as he progresses, but correct any negative behavior immediately. If you need help, consider an obedience or socialization program. The local Petco may offer one or both.

That is quite young for a puppy to be very scared of everything. If you just got her a few days ago, it may take time for her to adjust (usually 2-3 weeks) before she fully feels herself. However if she is acting so scared that she won't interact at all, isn't eating, or wanting to do normal puppy things (playing, exploring, etc), it is best to seek out a veterinary behaviorist in your area. They can help ensure that Bella starts receiving positive socialization in her environment and with her new family to try and help with her issues. You can learn more about veterinary behaviorists here: http://www.dacvb.org/about/member-directory/