Hm, there seems to be mixed opinions on this. Some factors depend on the material that the bags are made of, if there are any stickers or labelling on them, and how they’re sealed. You may find some of these threads helpful:
Cooking in original vacuum package
Morton’s Marinated Tri-Tip from Costco
Pork tenderloins in the vacuum bag from store
On the link you provided, it notes “Remove all packaging.”, which is a good indicator it may be “food safe” but not “cooking safe”.
I would go ahead and freeze the chicken in the original packaging but when time to cook, remove the original packaging and follow the steps of using a zipper lock freezer grade bag or silicon bag.
The only time I’ll cook with the original packaging is if the cooking instructions say suggest “drop in boiling water”.
I have noticed recently that both Morrisons and Lidl are selling some of their steaks in vacuum sealed packs so I have contacted the customer services of both supermarkets to ask if it is safe to use them in their packaging at up to 60 C as I tend to cook my steaks to 54.5C.
If and when I get a reply I will update this thread.
I also bought one of these today to see if it would be a suitable container to use as a water bath.
I tested it up to 90 degrees C and it held it’s shape but the outside was obviously hot to the touch so needs to be placed somewhere safe if using at high temperatures. it comes with a lid to that I may make a cut out in to allow the Anova to fit through it to stop the water evaporating. I also bought the 20 litre box and asked if they did one in between those two and was told no, but when I went online I saw that they do a 14 litre one that I have now ordered to be delivered to the store.
The smaller 5.6 litre one looks to de an ideal size for cooking one or maybe two steaks while the 14 litre looks like it will cook enough for a family. The large one I can use for storing all the other boxes, the Anova and the vacuum bags in and then I can sit it on top of my fridge freezer when I am not using it. So at only £6 for all 3 of those boxes and lids I think they are a bit of a bargain
I finally got a reply from Lidl saying that their packing wouldn’t be suitable for sous vide as the glue sticking the clear film to the black plastic would not stand the temperature and would allow the film to separate.
Despite trying to explain to Morrisons customer support what I was asking them about they just ignored me after my third email to them but as the packaging was very similar to that used by Lidl then I suspect that theirs would not be suitable either.