Thank you for your patience. Rocky's apparent straining now is likely still related to his diarrhea rather than him being constipated. With a few days of diarrhea, dogs can develop 'tenesmus' which makes them feel like they need to go to the toilet a lot, but all they will do is squat and strain (with nothing coming out). This can occur due to irritation and a little pain from several days worth of diarrhea. The fact he hasn't had a bowel movement at all now for 3 days is definitely a concern however, and we even have to consider whether Rocky could have ingested something that could have been come stuck in his abdomen. It is great he is still hungry and is eating the chicken and rice without an issue. Make sure the chicken is skinless, boneless and well cooked to avoid any other issues here.
For now - you will need to continue to encourage his water intake primarily, as they will be the key to get things moving for him. Continue to feed him the chicken and rice as you have done already and hopefully you see a nice bowel movement overnight. If not - you will definitely need to get him to your local vet first thing tomorrow for a check up and diagnostics to see why he hasn't had a bowel movement in so long.
Please keep a close eye on his mucus membranes, capillary refill time and respiratory rate as follows:
Mucus membranes - flip his lip and look at the color of his gums. They should maintain a nice salmon pink color. Get him to the emergency Vet if they appear white or very pale pink, or if they are a dark deep red color.
Capillary Refill time - this measures blood perfusion and test this by putting your thumb on his gum to apply pressure. After you release your thumb you will see the gum blanch. Capillary refill time is the amount of time it takes (in seconds) for the gum to return to a healthy pink color from the blanched white color. If 2 seconds or less don't worry - if it is taking significantly more time, again - off to the emergency Vet.
Respiratory Rate - if he is continuously panting throughout the night, this is a sign of shock and or pain and a signal for a trip to the emergency Vet.
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