Thanks for the replies. We wrote the below up as our findings, running to a veterinarian to pay hundreds of dollars for a examination or post mortum was not an option. People are free to make their own conclusions from that and what we've added on our experience below.
We are not avian veterinary specialists however concluded that the chicken death and chicken suffocation was the result of feeding laying pellets that they were not used to eating. So our diagnosis was Pellet Obstruction/Suffocation. We were just recently gifted a 10kg bag of laying pellets, our chickens are used to eating much smaller wheat (images of size comparisons included below). We never purchase the laying pellets as we have actually had bird deaths in the past a few years ago when feeding these out however never really made any connection. Forgetting previous experience we fed these out and found one chicken dead. The next day after feeding the same laying pellets again we found another chicken gasping for air. We realised that the bird was obviously suffocating on the laying pellets (no it wasn't a respiratory condition from its environment nor a viral infection) and that this was most likely the cause of our other chicken's death who we had buried the previous day.
I don't know the exact size of a chicken oesophagus however it was very obvious that the chicken was suffocating and if we had not acted it would have died within minutes. Unfortunately we had to act ourselves as no one else would assist (no one is willing to help you with a rooster you see). The hard laying pellets measure 15mms in length the wheat measures at most 5-6 mms in length (that is a differential of 3 times the size.
We did some experiments afterwards and placed separate pellets in lids of water to gauge how long it would take to break down. We always have water available for the chickens to drink from. The first pellet was not fully submerged and broke with force from pen after 3 minutes (it was still hard). The second pellet which was fully submerged broke apart easily after 2 minutes 32 seconds. Note that these pellets had surrounding water for full absorption, a pellet lodged in a narrow chicken’s oesophagus would take much longer to allow for water to be absorbed.
The symptoms of the chicken were that it was stretching out its neck gasping for breath, it will not move and in fact become unable to stand, its eyes will begin to close shut, its head will fall and it will eventually pass out from lack of oxygen. At the sign of the first symptoms we had driven around looking for help. Finding none we brought it home. We began to squirt small amounts of luke warm water into the back of the chicken's mouth. Thanks Toddrick for above image and comment "you shouldn't really force liquid into the birds beak unless you carefully do it off to the far left side (opposite the trachea)" using a syringe applicator to help dislodge/loosen the pellet blockage. It is important here to state that even though we always have water available for the chickens to drink, a pellet that has already become lodged will require your manual assistance to resolve or the chicken will shortly die of suffocation (ours collapsed several times almost completely lifeless that we thought it had died, it had passed out from lack of oxygen – a gentle but firm stir managed to revive shallow breathing) and if anyone has ever experienced choking on food then the last instinctual thing you want to do is add anything else that will obstruct the oxygen pathway.
This is the plastic needleless syringe we used to squirt luke warm water to the back of the mouth (we did not place in throat). These are the sort that can be picked up from chemists for a few dollars. An eye dropper can also be used. If nothing else is available on hand improvise. A teaspoon should suffice. After repeated water doses we gave one small dose of warmed coconut oil 15 mils (vegetable oil will serve the same purpose) to assist to sooth and lubricate then returned to water.
Each dosage of warm water was around approximately 20mils or a teaspoon or two amount (much of which did not go down or was spat out), given every few minutes as required pro-re-nata and then perhaps 10-15 minutes as gasping slowly began to reduce. The chicken regurgitated the water several times but a certain amount passed. During this process we also used the syringe applicator to squirt a teaspoon of warmed coconut oil into the back of the chicken’s mouth to lubricate as we found someone had done while we frantically searched the internet for solutions. The chicken passed out totally collapsing several times from lack of oxygen during the time the pellet obstruction broke down but we managed to revive its breathing, it also lost full control of its bodily functions. Eventually after this ordeal the gasping settled to a wheezing breath an hour or so later as the water took effect on the pellet obstruction. The chicken began able to stand and slowly walk seeking out a dark spot to bed down in for the night. The breathing slowly settled as we checked during the night and the following morning we have found the chicken walking and fine although understandably reluctant to eat. It took a couple of days for the chicken to recover its crow (probably recovered too well as now it wont stop crowing). We have never fed the laying pellets since and never will again and turned the rest to mash by adding water.
No virus was present as far as we could tell nor have any other chickens been affected since we removed the laying pellets as a food source (although one hen has gone into a depressed state since her mate has died), so through process of elimination we have concluded this is the result of pellet obstruction/suffocation. With all caution, this is our experience of which we managed to save our chicken's life (when those avian specialists we contacted via phone offered nothing but to let the process play out thereby letting it die) so we wanted to add it so that it provided an option for others to choose from who may find themselves in a similar situation.
Feel free to add comments and constructive criticism.
Edited by Stone Hobbit - 11/15/15 at 1:22pm