Border Terrier off colour - Kong?

[Milicentbystander72]

Last week my Border Terrier was a bit sick and off colour. Trembling a bit. He rested for a day and I offered him chicken and rice. After a day he was fine. I gradually reintroduced his kibble. All fine.

However this evening he's off colour again with a little tremble, like when he's scared of fireworks. He was fine this morning, out for a long walk - ate his midday meal fine.

The only thing I can think of is I gave home a King earlier, filled mainly with kibble but with pate smoothed into the top half for him to lick out. He's had this before no problem but I'm wondering if it was too much and too rich?

Any ideas? If I work out that it is the Kong what other things could I put in it?

[Girlintheframe]

Things I've put in the kong
Mashed banana
Beef stock (tape up the small hole then pour in beef stock and freeze)
Beef stock with kibble
Peanut butter (sugar and sugar sub free)
Grated carrot
Pate
Cream cheese
Beef stock with bits of ham/chicken
If you have a google there are loads of suggestions

[StrictlyNameChangin]

I'm sorry I don't know the answer, but could I ask you a question?! How do you clean your Kong?

[Girlintheframe]

I wash it by hand to get an obvious bits off then put it in the dishwasher