FYI, unless you plan on using the litter for compost, sand is substantially healthier than pine shavings.
Actually, the study you cited does not give any evidence to support this at all. It mentions that no effort was made to identify the species or pathogenic qualities of the bacteria present. The only conclusion it draws is that there is more bacteria present in shavings vs sand. Neither does it report on the health or mortality rate of the chicks in the study.
As for the sand vs shavings debate you often read in posts here, they are often regarding which is "better" from a moisture abatement and absorbency standpoint. The study would seem to bolster the claim that shavings are more absorbent (lower water activity/higher moisture content) than sand.
Additionally, I wonder what the results would be for a long term study from a run exposed to fresh air and sunlight and dirt below (I'm guessing they weren't putting those day old broiler chicks outside). The conditions of this study vary too much from my "real-life" conditions for me to be able to extrapolate much useful information from it.
If I bought this off amazon, is it still covered under warranty?
. The heat lamp I only turn on if it gets below 32 Degrees as they are only still 6 weeks old today. All I can go off of is information from other chicken owners, no real good "cited" source to actually compare too. Word of advice to anyone thinking about building their owncoop, go off of building plans, I winged this one for about 3 weeks, and If I had to do over again after $550 bucks of just lumber alone, I would have just bought a shed lol