My 15 year old silky terrier who is half blind and arthritic but otherwise in reasonable health has for the last 8 months or so occasionally choked on her food. She will eat and then start gagging/choking and sometimes vomit up the food.
I put it down to the fact that she doesn't have many teeth therefore would mash any lumps in her food which seemed to help, up until recently. Over the last couple of days she seems to be having a lot more trouble swallowing and is bring up her food more often even though it is thoroughly mashed Apart from this she appears to be her normal self. I worry that she may have something growing in her throat and it is getting narrower? She has lots of growths in her ears that have been there for years.

When was her last vet visit? Older dogs should visit the vet twice a year for check-ups.

Old animals including people have trouble swallowing. Partly weak muscles of the throat, sometimes lumps in dogs, who tend to get lots of lumps. Or it can be tumors, of course. It can be stomach problems. At 15 I would expect this. I'm not sure the vet will have much to say. There are special diets for old dogs. When my golden got old he got cancer and the vet said just give him whatever he wants to eat, so I gave him hamburg, eggs, anything that went down.

She goes to the vet about 3 times a year, she is on prednisone for her arthritis so usually it is for more tablets and she continues to have problems with one of her legs but apart from that she has been plodding along quite well for her age. I have stopped giving her chopped cooked chicken, which was her favourite, because that is what she first started to gag on so I assumed it was too lumpy to go down her throat. I thought because she has few teeth that it was being chewed up small enough, I don't think that is the case now. I will be taking her to the vet to have her checked tomorrow.

If she likes chicken, mash it up in a food processor or baby food grinder or with a knife chop it up very, very small. And add broth. Feed her a little bit at a time and make sure it stays down before the next bite.

Please take her to a Vet. She is really old for a dog, and needs special care. The oldest of my three dogs is 11 yrs old, with arthritus, too. She is on Tramadol, 100 mg a day, weighing in at 74 lbs... a lab. The Vet said the only thing that can be done is make her comfortable, and keep her out of the cold for long periods. She is a house dog. Please take yours to a Vet, and see if anything can be done. Good luck.