Hi Marylou- Do you know if there are any remaining parasites from the Giardia? She could still be feeling sick from that or the meds and not want to eat. Also, I do know that most Poodles (at least standards) tend to be on the thin side. You can usually see their hip bones etc unlike with other breeds. Have you asked the vet about her weight? I would definitely seek the opinion of a vet over a groomer (no offence). If she was weighed at the vet and her weight was not brought up she might actually be a normal weight.
If you want her to gain a little weight, you can give her coconut oil. Dogs love the taste and it’s high in calories. You could try adding it to the food as well. Also there is nothing wrong with adding chicken breast to her kibble. However make sure it’s not overcooked. It should be boiled if anything.
