TL, DR: Compact chicken cookers, as currently designed, should still function with 24 egg-laying chickens, and should output about 20-40 cooked chicken per hour.

Disclaimer: I'm not complaining about the new rule, just showing how the new rule affects chicken cookers.

Consider a chicken cooker design which has 24 chickens standing on a single hopper, which uses a dispenser to hatch their eggs and cook the chicks when they grow to be adults.

According to the wiki, the probability that an egg will hatch a single chicken is 31/256, and the probability that an egg will hatch 4 chickens is 1/256. Therefore, the expected number of chickens per egg thrown is 35/256, or 0.137.

Baby chickens take 20 minutes to grow into adults. Let's first assume that every adult egg-laying chicken lays an egg every five minutes – the fastest possible rate. Then each chicken lays 4 eggs in a 20 minute period – a total of 96 eggs.

(96 eggs) * (35/256 chickens per egg) = 13.125 chickens.

So if all your egg-laying chickens lay eggs as fast as possible, the expected number of new baby chickens born in a 20 minute time period is 13.125.

If all your chickens lay an egg every 10 minutes – as slow as possible, then we have:

(48 eggs) * (35/256 chickens per egg) = 6.5625 chickens.

What this means is that these farms, as currently designed, would be unlikely to produce baby chickens fast enough for them to suffocate before reaching adulthood and being cooked.

Also, we expect that these farms, as currently designed, would produce between 6.5625 and 13.125 cooked chicken per 20 minute period, i.e. 19.6875 to 39.375 cooked chicken per hour.

Of course, there will be variation, but this gives us a rough lower bound to work with.