Statements: • All chickens are birds. • Some chickens are hens. • Female birds lay eggs. Conclusions: I. All birds lay eggs. II. Some hens are birds. III. Some chickens are not hens. Select the option that must follow.

Introduction / Context:
This syllogism blends universal and particular statements with a qualifier (“female”). The task is to avoid overgeneralization while recognizing secure existential consequences.

Given Data / Assumptions:

• All Chickens ⊆ Birds.
• Some Chickens are Hens (∃x: x ∈ Chickens ∩ Hens).
• Female Birds lay eggs.
• By definition, hens are female chickens (hence female birds).

Concept / Approach:
From “Some Chickens are Hens” and “All Chickens are Birds,” we can assert existence of hens that are birds. The statement about egg-laying is restricted to female birds, so it does not license “All birds lay eggs.”

Step-by-Step Solution:
1) Since Chickens ⊆ Birds and some Chickens are Hens, we have some Hens that are Birds ⇒ Conclusion II is true.2) Conclusion I (“All birds lay eggs”) overgeneralizes. Only female birds lay eggs; male birds do not. Therefore I is false.3) Conclusion III (“Some chickens are not hens”) is not forced. The premises allow all chickens to be hens or only some; there is no guarantee of a non-hen chicken.

Verification / Alternative check:
Model 1 (compatible): All chickens are hens. Then II is true, III is false. Model 2: Only some chickens are hens; II still true, but III may or may not be true depending on numbers. Because III is not necessary, it does not follow.

Why Other Options Are Wrong:
Options asserting I or III are incorrect because neither is entailed in every model.

Common Pitfalls:
Reading “female birds lay eggs” as “all birds lay eggs,” or assuming “some A are B” implies “some A are not B.” Both are classic errors.

Final Answer:
Only conclusion II follows.