Ah, ya:

For the reformed scenario, represented by the use of a slower-growing strain, we assumed an average ADG of 45-46 g/day, hence that the same slaughter weight would be reached in approximately 56 days.

I think it's worth noting here that (if I'm understanding it right) the alternative breeds recommended by the better chicken commitment are slower-growing but don't have a lower max weight.

I'm not sure, but the optimal weight at slaughter could be lower, which I think Lusk et al. (blog post) found for the US. Even if they could reach the same maximum weight, it may be more profitable to slaughter them at lower weights.

And the welfare footprint project numbers on pain durations already account for the longer time to reach full weight. 

Ya, I intended to imply that, but could have worded things better. I've edited my comment.

Welfare Footprint Project has analysis here, which they summarize:

Adoption of the Better Chicken Commitment, with use of a slower-growing breed reaching a slaughter weight of approximately 2.5 Kg at 56 days (ADG=45-46 g/day) is expected to prevent “at least” 33 [13 to 53] hours of Disabling pain, 79 [-99 to 260] hours of Hurtful and 25 [5 to 45] seconds of Excruciating pain for every bird affected by this intervention (only hours awake are considered). These figures correspond to a reduction of approximately 66%, 24% and 78% , respectively, in the time experienced in Disabling, Hurtful and Excruciating pain relative to a conventional scenario due to lameness, cardiopulmonary disorders, behavioral deprivation and thermal stress. 

The reduction in suffering per chicken is probably >24% if this analysis is correct, and it accounts for longer lives. My guess is >50%, giving substantial weight to disabling pain relative to milder pain. Accounting for more chickens necessary for the same amount of meat (EDIT: although WFP assumes they grow to the same weight) wouldn't flip things. (And there would be a reduction in demand to partially offset this, due to higher costs per kg of meat.)

Lameness-related pain primarily due to their breed seems to be the largest source of their suffering and responsible for a lot of suffering, so it makes sense to me that slower growing breeds would be better off.

Are you effectively assuming that when they are awake and not experiencing hurtful pain or worse, that they are experiencing pleasure as intense as hurtful pain? I would probably assume only pleasure that intense for eating, dustbathing and playing, at most. Foraging might be annoying or hurtful intensity.

Related thread here.

Given your (partial) success in court (reported here and here), have your plans changed for what you'd use extra funding for? And has the funding gap changed? Your post says:

We will now explore bringing private prosecutions against mega-farms that use Frankenchickens.

I could imagine that a higher human population could induce demand for agriculture and increased trash output which could increase terrestrial invertebrate populations.

So this would be more food/net primary productivity available for terrestrial invertebrates to eat, and agriculture would have to increase net primary productivity overall (EDIT: or transform it into a more useful form for invertebrates), right?

My best guess is that more humans reduces wild terrestrial invertebrate populations in the near term / on Earth (so ignoring space colonization), largely through agricultural land use.^[1] If you think:

1. these wild invertebrates or even just wild insects matter a decent amount, say about as much as RP does/would (interpolating their estimates), and
2. they have lives worth preventing, because you're suffering-focused or just think they have net negative lives, say, due to their high fertility and mortality rates,

then increasing human populations could be good for animals in the near term, with the effect on wild animals outweighing those on farmed animals.

It's unclear to me what's going on with wild aquatic animals.

1. ^{^}

   See especially Tables 3 and 4 from Attwood et al., 2008.
   Net primary productivity is also typically lower in crops, across crops, based on "Land Use Change" greenhouse gas emissions from OWID / Poore & Nemecek, 2018.
   Gross primary productivity decreases when replacing forest with crops, but increases if replacing grassland with crops, according to the globally representative study Krause et al., 2022.
   Some other studies support increased and others decreased net productivity in crops compared to nature (Tomasik, 2013–2022, a, b)
   But pesticides and fertilizers also plausibly reduce arthropod populations based on my lit reviews (but less clear in the long run with repeated use), so even if primary productivity increased, arthropod populations could still be lower overall.

I'd guess other forage fish's life histories will give you a general idea of bristlemouths' life histories.

About Peruvian anchoveta, one of the most wild-caught fish, representing 28% of the number of fish caught annually on average (Mood & Brooke, 2024), Molina-Valdivia et al. (2020) write:

Early larval growth and mortality of anchoveta is highly variable at intra-seasonal and latitudinal scales along the Chilean coast. In northern Chile (23 °S), larval growth varies between 0.50- and 0.85-mm day−1, with daily losses of 16–23% (Contreras et al., 2017); meanwhile, in central Chile (36 °S), larvae grew at 0.40-0.57 mm day−1, with daily losses of 4–7% (Castro and Hernández, 2000; Hernández and Castro, 2000).

See also Fig. 4. H (and G for another species) for the drop in abundance over time as larvae, leaving less than 1% after 40 days according to their fitted model.

Butler et al. (1993, Tables 1, 2, 3 and 4) report fecundity and mortality estimates for northern anchovies (Engraulis mordax) and Pacific sardines (Sardinops sagax) at various life stages. A female northern anchovy spawns 5.3 to 23.5 times per year, 4,000 to 14,000 eggs each time. I have some calculations for mortality rates at various life stages based on this paper here.