Why is my senior Chihuahua barking constantly after her friend died?

At his age, it could be a degree of canine cognitive dysfunction (senility). You would need to have Chewy examined by your veterinarian for confirmation. If this is the case, there are medications and other treatment options. https://www.petcoach.co/article/aging-gracefully-6-things-to-know-about-canine-cognitive-dysfunct/ https://www.petcoach.co/article/4-signs-of-cognitive-dysfunction-in-dogs/

I would recommend taking Mia to the park and get her energy out of her. The more you exercise her and get her energy out the better. This will make her as tired as possible which will make her less inclined to have the energy to bark. I would also talk to your veterinarian about anxiety medication. This was a big transition for her and she may need time to adjust to the change. I am so incredibly sorry for your loss and wish you peace in your time of need. Thank you for using Petco Pet Education Center, formerly Petcoach.

Hi there and thank you for using Petco Pet Education Center, formerly Petcoach to address your concern. Animals do show emotion and it very well could be that she is grieving or missing your 12 year old dog. If they were together for a long time, and now your other dog is missing, this is a big change in Kita's environment not having her friend around. I would recommend providing her with plenty of toys to play with and take her out a lot. If this is due to emotional stress, it should hopefully resolve with time. If any new symptoms develop I would recommend having a veterinarian examine Kita and test her blood for any abnormal changes. I hope this helps! Please let me know if you have any other questions or concerns and I would be more than happy to help you further.

It is probably worth getting her seen by your vet since any changes of behavior could indicate changes in her mentation, she could be getting hard of hearing and/or her sight may not be good. Since she barks when you aren't nearby, I suspect she may be losing her sight. That could be what is causing her to scratch, since maybe she can't see to get to the door as before. Also, the change in environment in the new home could be confusing her, especially if she lived for a long time at the old place.

I'm sorry to hear about your issues with Cotton. It sound like he is suffering separation anxiety. This can be a standalone behavior problem, but when it develops suddenly in older pets, it can indicate a change in health status such as hearing or vision loss. This is a good resource for managing separation anxiety, but if you do not see improvement, I would recommend having Cotton seen by your veterinarian to ensure there is nothing else going on. https://drsophiayin.com/blog/entry/separation-anxiety-solution-training-fido-that-calm-behavior-makes-you/

I would increase her exercise and keep he up during the evening so she is very tired at bedtime. You also can give Benadryl to help her sleep. You can find the dose on this website. If it continues you can get relax medication from your veterinarian or you can try a Sonic Egg from PetCo. It will emit a sound when she starts to bark. Usually this will stop this behavior quickly. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for Chrissy.

This could be anxiety as you suggest, or it could be canine cognitive dysfunction (doggy dementia). CCG often includes restless/wakeful behavior at night and sleeping during the day. It can also include loss of house-training, failure to recognize family members and confused or wandering behavior. Melatonin and/or Benadryl are considered generally safe medications to give before bed to help promote sleep. There are also medications and prescription diets made especially for CCD if that is what’s happening to Sherwood. Talk with your vet to see if s/he agrees and to discuss options and doses.