How can I fatten up my chihuahuas? They are healthy, but I can see their bones! Please help!:( :(

Start with the ''My dog won't eat sticky'',
https://www.askmehelpdesk.com/dogs/information-articles-our-dogs-expert-labman-53153.html#post254171

Have you talked to the vet about it? Does the vet agree they need to gain weight? It is very rare for a healthy, happy dog not to eat all it needs. Don't look at the average Chihuahua as an example. Most of them are over fed and too fat for their good.